I'm goin' CRAZY!!!

[DanL]

Fred,
The Canon Axxx series is nice, and Canon makes housings for them (be sure to check which have compatible housings).  As A&A points out, a nice setup just a bit above your minimum price range.
But here is more to make you "going crazy".
Now you need to consider if the camera flash modes will be compatible with the strobe you might want to get - does it have a slave trigger flash mode? etc. 
Also, you will soon find that you might want to add a lens -  either wide angle or macro.  The Canon made housings for the 6xxx series have an oval lens port, not round like mostly all others, so you won't be able to add an external add-on lens.
The strobe and add-on lenses may not be in your plans now, but think about them when making your choice so that you have the foundation of a system if you do want to expand your equipment.