Hi Barry,
In answer to your question, I keep all my poker bankroll split between several sites - Stars, Full Tilt, DTD & Blue

. I used to use Neteller as an intermediary to transfer funds between sites but withdrew what little I was holding there last year when there was all the uncertainty about the future of Neteller. However, my account is not closed, so I may resume using it again if necessary.
Another method of transferring funds is by friends on IRC. Occasionally someone would ask to swap, say, $200 Stars for Full Tilt funds, and we tend to help each other out. This is very quick and efficient, so long as you can trust the other people. I've known them for a couple of years and have never had any problems so far.
Mark.