I never liked using the bike mounted water cages. I tend to look to grab or put it back... and off my line I go (you remember me, spazz is the name - crash is the game).

Any-hoo I bought this behind-the-seat saddle mounted cage rig (Xlab Saddle Wing) and thought I'd died and gone to heaven. I just reach behind my butt and pull... oooh, that sounds a little weird. But you get what I mean... I hope

Xlabs can be found at triathlon gear places. I use Tri-zone.com

They also have a rig that clamps to your seat post. I had one of those also but couldn't use it on my new bike because of the carbon fiber seat post.