1. Tim DuncanKarl Malone was the standard for so long (in the three point era if nothing else), but it has to be Duncan. He averaged over 20 and 11 his first eight years in the league (1998-2005, which included a couple of seasons where he played less than 70 games and the lockout shortened 1999 season), winning three of his four titles during that span including that near quadruple double in the 2003 Finals, is as fundamentally sound as anyone who's ever played the game and brilliant at both ends of the court; at one end, dependable post moves and respectable range on his jumpshot, at the other simply superb all around defense.
If we were to subscribe to the idea that players of a certain position must be this or that, then Tim Duncan is what a power forward should be. I'll be a little less black and white about the matter and say that if you're building your team around a star power forward, you're going to want him to be like Tim Duncan.
2. Karl MaloneOr Karl Malone. The Mailman ranks second on my list these days but he's still a great choice for the prototypical power forward. He could flat out score the basketball, was good for a double double (or close enough to it) for over a decade, with his prime probably being 1989-1995, though it's possibly a toss-up with 1991-1997. One of the league's true iron men who could bully opponents in the paint and punish them from midrange, I'd have to rank him lower than Duncan defensively and he wasn't quite as dependable as a clutch performer. No way I can rank him any lower than second though.
3. Kevin GarnettThis was a tough choice as I felt this spot should be Charles Barkley's and he'd be something of a sentimental choice since he's one of the players I grew up watching. However, KG is the superior defender and a multi-talented player who was right up there with Tim Duncan for the better part of a decade or so. From 2001-2007 he put up some fantastic numbers to the tune of around 22 and 13 and while his Timberwolves teams had their shortcomings, he was one of the top two or three power forwards in the league during that span. I've got to give him the third spot.
4. Charles BarkleyWith KG getting the third spot, Sir Charles makes the list at number four. Defensively, I'd rate him lower than Duncan and Garnett and probably more favourably with Malone, but his rebounding numbers were phenomenal for a player his height. Only once in his career did he fail to average double digits in rebounds and that was his rookie year, when he played less than 30 minutes a game and came off the bench for 22 games (per 36, his rebounding average only drops to single digits in 1991, at 9.8 per game). He was also pretty well rounded for his position at the offensive end, being able to knock down a decent number of threes and midrange shots while doing damage down low and of course on the offensive glass. 1987-1993 was probably the best seven years span of his career.
5. Dirk NowitzkiConsidering the
favourable comparisons with Larry Bird, I don't think it's out of place to rank him in the top five. Deceptively one of the best low post scorers in the league while at the same time having more range than anyone else on the list, he's truly an outstanding offensive player and incredible shooter...and probably a better defender than he's usually given credit for (though not at the level of a Duncan or KG). Despite the stereotype of disappearing in the clutch, he lacks numerous examples of underperforming in key games, important series and crucial fourth quarters that could be cited for other players with a reputation (deserving or not) of disappearing in crunch time. The 2011 Finals have probably finally dispelled that myth for most people.
His 2011 season could probably be considered one of the best of his career, in which case I'd choose 2001-2006 as the other six seasons. It's kind of hard to choose for Nowitzki as looking back, he's been impressively consistent through his career right up to and including last season.
6. Kevin McHaleMcHale's career numbers, while still outstanding, aren't quite as gaudy as some of the other players on the list. He never averaged double digits in rebounds (well, he came close enough in 1987 with 9.9) but then he did play with Larry Bird who was putting up amazing numbers. He shot the ball extremely well though connecting on 55% of his attempts throughout his career, twice topping the 60% mark and only once shooting below 50%. He didn't have the range of some of the others in the top ten but he had a tremendous post game with fantastic footwork and a wide assortment of moves. And he did it all playing most of his career off the bench, though admittedly he was a frequent starter for much of his prime (1984-1990).
7. Pau GasolHard to rank Gasol any lower than this. Great scorer with good hands and offensive instincts, a solid rebounder (though his numbers aren't eye-popping given his size), somewhat of an underrated defender at times. Solid in the post and out to midrange, good ballhandling and passing for a big, fairly steady at the line and shoots a good percentage. I don't think he's as soft as he's sometimes painted as being but he does seem to lack assertiveness at times. Nevertheless he belongs in the top ten (can't believe I forgot about him the first time around

). A bit difficult to pin down the best seven years of his career to date but I'll go with 2004-2010.
8. Chris WebberC-Webb's career was dogged by the timeout debacle at Michigan, along with an assortment of injuries and disappointment in the Playoffs and it pretty much fizzled out after his retirement in 2008 following nine ordinary games with the Warriors. However, he was a very talented player who was a 20-10 player for the six of the seven seasons spanning 1997-2003 (9.5 rebounds per game in the other year). You could possibly through his 2005 season in there as well, where he was again averaging 21 and close to 10 boards before the trade to Philadelphia.
I'd say he represented a bit of evolution at the power forward position that players like KG and Dirk ultimately took a little further and did better; he had a "traditional" offensive game for a big man but also had range on his jumpshot, being a decent three point shooter early on in his career. He was also part of a wave of power forwards who were a bit too big and not quite skilled enough with the ball to be point forwards, but still had very good ballhandling and passing skills for their position.
9. Dennis RodmanCharles Barkley's rebounding numbers were phenomenal. Dennis Rodman's were off the charts. Per 36, he never averaged fewer than 10.3 boards per game. He collected seven consecutive rebounding titles and posted back-to-back seasons of 18 plus rebounds per game, all while being listed generously at 6'8" and battling much bigger players. A pesky defender with good instincts, his skill as a player was all too often overshadowed by his off-court antics later in his career, so it's great to see him finally inducted into the Hall of Fame. He also wasn't too bad offensively; he didn't really have a jumpshot (the odd three or midrange shot he'd bank in aside) or a plethora of offensive moves but his focus on defense and rebounding made him an unselfish passer and netted him many garbage baskets over the years. His run of rebounding titles from 1992-1998 were probably his best seasons, though he posted better scoring numbers earlier in his career with the Pistons.
10. Shawn KempWhat could have been...Kemp should've been a star in the league much longer but as recently mentioned elsewhere, the lockout of 1998/1999 really did a number on his career as his weight ballooned, a few person problems intensified and he found himself struggling to lead lousy Cavs teams then riding the bench in Portland before a semi-respectable final season with the Magic. He had some great years in the mid 90s though, not too far under being a 20-10 player from 1992-1998 (and pretty much there Per 36; he never played more than 35 minutes per game) and was pretty versatile at his position. Kind of similar to Webber but a bit more turnover prone. He was spectacular in the 1996 Finals, too.
Honourable Mentions: Amar'e Stoudemire, Elton Brand, Larry Johnson, Larry Nance, Vin Baker, Charles Oakley, Buck Williams, Lamar Odom, Derrick Coleman, Kevin Willis, Anthony Mason, Tom Chambers, Antoine Walker.