I will only deposit at Pokerstars, even when others offer deposit offers etc
I play on FTP, PP, (not 888, its crap) and the various Poker Clones (the ones that all like themselves like Titan, Winner, William Hill, Gala, 777) for the freerolls.
I am a bit brasic for depositing at the moment so any money i earn from the Freerolls (got ?2 in a 4700 field 9th place finish on a PP FR and 390 in the 100k depositor freeroll for 45c [wohoo!!]) i just put into playing games.
The PP freeroll that earned me ?2 let me invest in a 200 man tornament that ended up getting me a good $16 in money for a final table finish (i forget what place) and and i put that into playing in the $1 SNG's that PP has so i am working on improving that bankroll there but if someone gave me ?10 to put on a poker room, i would pick Pstars
FYI : The country specific freerolls offer nice fields (like 300-600 for the UK) with even a couple of ?2 for a 21st place finish! so if you pair your Pstars / TP account up you can xfer it over when you win and play it on Pstars ;)