Help Choosing Servos

I was wondering what servos people use?

Which ones can be modified for continous rotation, and which ones are usefull for moving sensors and the such.

Avability in the would be a positive, but not necessary!

I've generally used Futaba servos; when I was buying, they were easy to get hold of, cheap and easy to mod.

Depends on usage; the 3003s I've had in the past are OK, but with plastic gears, are not as long lived or robust as metal geared servos.
Buy 'em online, or from model shops.