If you just want very basic power selection, set up a profile at herocorps.com (or creyindustries.com for heroes)
Is it time for the dance of joy yet?
http://home.comcast.net/~SherkSilver/index.html
(I assume thats the one everyone uses)
http://joechott.com/coh
(I used this think its a little out of date and doesn't have as much detail isn't as pretty but seems to do the job quite well?)
Apart from the one everyone normally uses... 'coz I can't use that one... :S