Just about every professional basketball-related website has a power rankings page, so here's a summary of some of the most prominent.

Power rankings sites fall into 2 basic categories. 

I will refer to the first as "Statistics-based", where there's a mathematical formula which yields the rankings (and is therefore unbiased). Best known examples are ESPN's (John) Hollinger rankings, which update daily, and Neal Paine's primarily point differential-based model on basketball-reference.com.

I call the 2nd type "Opinion based", where a sportswriter (or team of same) votes based on whatever criteria they decide. These are generally updated weekly, and are more apt to give more weight to the last 7 days of a team's performance than the stats-based. Examples of this type are Marc Stein's ESPN page which updates on Mondays and SB Nation's which updates on Tuesdays - so their Allstar Break editions won't be up until early next week. 

Statistics-based:

Let's start with the biggest, if not the best - the Miami Heatles Hype Leader, the site with a team of writers focussed solely on the Heatles - highlighting the only team with a tab on the NBA Home page (the Heat Index) - ESPN http://espn.go.com/nba/hollinger/powerrankings

THE TOP 10:

Heat 41-15

Spurs 46-10

Magic 36-21

Bulls 38-16

Celtics 40-14

Lakers 38-19

Mavs 40-16

76ers 27-29

Thunder 35-19

Hornets 33-25

Comments: Hollinger uses a simple W-L record to determine Strength of Schedule - but then doesn't give it a whole lot of weight in his formula, which one reason why the Heatles are #1 despite having the league's 2nd easiest schedule to date.  It gives the highest weight to point differential, as with most stats-based systems. There are often anomalies such as the 76ers at # 8 despite their below .500 W-L record. Here's the link to his formula:

 http://insider.espn.go.com/nba/insider/columns/story?columnist=hollinger_john&page=Rankings-Intro&action=login&appRedirect=http%3a%2f%2finsider.espn.go.com%2fnba%2finsider%2fcolumns%2fstory%3fcolumnist%3dhollinger_john%26page%3dRankings-Intro

Next is basketball-reference.com.

http://www.basketball-reference.com/blog/?cat=50 

This one is 100% based on point differential, as is the strength of schedule, and the team's offensive and defensive ratings. Note the absence of the 76ers in the top 10 - but it still shows a lack of reality as the Heatles are ranked above a team they are 0-3 against (Celtics) and another they are 5 games/9% behind (Spurs)...  The model began from a stats guy on their related site, pro-football-reference.com - this explains the concept: http://www.pro-football-reference.com/blog/?p=37

Now, here's what the rest have to say:

http://www.nba.com/2011/news/powerrankings/02/14/week16/index.html John Schuhmann's top 3 were unchanged (heatles at #3)

1. Spurs

2. Celtics

3. Heatles

4. Lakers

5. Bulls

6. Mavs

7. Magic

8. Thunder

9. Grizzlies

10. Hawks 

http://espn.go.com/nba/powerrankings Marc Stein offers a very West-centered list (put down the heatles for the Celtics loss with their injured bench):

1. Spurs

2. Mavs

3. Lakers

4. Celtics

5. Heatles

6. Bulls

7. Magic

8. Thunder

9. Grizzlies

10. Hornets

http://www.sbnation.com/nba/2011/2/15/1994812/nba-power-rankings-san-antonio-spurs Tom Ziller gives the Heatles props for the close Celtics loss

1. Spurs

2. Heatles

3 Celtics

4, Lakers

5. Bulls

6. Magic

7. Mavs

8. Hornets

9. Nuggets

10. Thunder

http://sportsillustrated.cnn.com/2011/writers/britt_robson/02/15/power.rankings/index.html Britt Robson puts the Heatles third and pings Spoel for not giving Dampier enough tick vs the Celtics

1. Spurs

2. Celtics

3. Heatles

4. Bulls

5. Mavs

6. Lakers

7. Magic

8. Thunder

9. Grizzlies

10. Blazers

http://www.sportingnews.com/nba/feed/2010-11/nba-power-poll/story/power-poll-heat-still-cant-solve-the-celtics-but-are-clearly-improving Sean Deveney highlights the Celtics loss, posts a pic of Spoel complaining to a ref, top 4 unchanged

1. Spurs

2. Celtics

3. Heatles

4. Mavs

5. Lakers

6. Bulls

7. Magic

8. Thunder

9. Hawks

10. Blazers

http://www.hoopsworld.com/teams/Rankings.asp Eric Pincus changes things up compared to the others, with the Heatles again matching their low of #5. 

1. Spurs

2. Mavs

3. Bulls

4. Celtics

5. Heatles

6. Magic

7. Lakers

8. Thunder

9. Hawks

10. Grizzlies

http://www.docsports.com/2011/nba-power-rankings-035.html This one is Morey "Doc" Moseman's hadicapper service, who reminds that the heatles were favored to win the title over the Lakers (and also that they are just 28-27-1 vs the spread).

1. Spurs

2. Celtics

3. Heatles

4. Bulls

5. Mavs

6. Thunder

7. Lakers

8. Magic

9. Blazers

10. Hawks

In summary, the Stats geeks are predicting a Spurs-Heatles Finals.

The humans have a different view, favoring the Celtics...