Shaq has to be 1 or 2 among all big men, and you're missing a lot of centers. Shaq was essentially unstoppable the first 4-5 years of this decade and grabbed 3 titles in 4 Finals appearances during that stretch, getting only 1 MVP but deserving more. Then he went to Miami, should have won another MVP award, and helped Dwyane Wade and Bennett Salvatore win a title for the Heat. I would still put Duncan higher, but frankly, Shaq is still a bit ahead of KG for the decade as a whole.
If it's just big men, PFs and Cs, then:
1. Tim Duncan
2. Shaquille O'Neal
3. Kevin Garnett
4. Dirk Nowitzki
5*. Ben Wallace. It's easy to forget now, but he was on 5 All Defensive 1st Teams and a 2nd, and won 4 - yes, 4 - Defensive Player of the Year Awards (as many as Mutombo, more than Mourning, more than Duncan, KG, Camby and Howard combined). He also made 3 All-NBA 2nd Teams, 2 3rds, was a 4 time All Star, a huge part of a championship team, and shut down Shaq in the Finals better than anybody ever has. He averaged 11.2 boards and 2.35 blocks a game for the decade, including his later bad years. * - He may be retired now though.
6. Yao Ming
7. Dwight Howard
8. Elton Brand - injury prone as he's become and as many bad teams as he was on, he's the only guy other than Duncan, Shaq and KG to average 20 and 10 for the decade.
9. Amare Stoudemire
10. Chris Bosh
10*. If Wallace is considered retired - Jermaine O'Neal - though Gasol is much better right now, in O'Neal's first 7 seasons in Indiana he was a 19.1-9.9-2.45 blk guy, better than Gasol's 18.8-8.7-1.71, and his Indiana teams were very good, much better than Gasol's Memphis teams. Even factoring in his last two bad seasons, O'Neal still has better rebounding and block numbers than Gasol over the course of the decade, and is only a little behind him in scoring. O'Neal's rapid descent has made people forget how good he was for the first 6-7 years of the decade.
Top 10 power forwards of the last ten years:
1. Duncan
2. Garnett
3. Dirk
4. Brand
5. Amare
6. Bosh
7. J O'Neal (though playing as a center now, he started at power forward alongside Brad Miller or Jeff Foster during his prime years)
8. Pau Gasol
9. Rasheed Wallace
10. Carlos Boozer
I would put Chris Webber probably 4th ahead of Brand. While he got submarined in 03-04, he really was phenomenal the first 4 years of the decade (99-00 to 02-03) putting up about 25-10.5-4.5 ast-1.5 stl-1.5 blk on great teams. That's just so much better than anything those guys below him but up for more extended periods that I'd have to put him behind only Duncan, KG and Dirk. I'd also put Karl Malone, who played 5 of the last 10 years and averaged 21.8 pts, 8.6 boards, 4.2 assists and 1.39 steals in that time, ahead of Boozer and probably Sheed too.