For MTTs I prefer Stars - love the 15 min blind levels.
For STTs I prefer iPoker (usually at Titan) simply because up to the $55 game, they are so soft.
For Cash, it"s iPoker all day long - up to $1/$2 it"s just easy money.
iPoker is awful for standard MTTs below $50 buy in - they have quite a fast structure with many levels missing, no antes, and 10 minute blinds.
Best "fun" tourney is the Sky Open, although I wouldn"t dream of playing that to try and make money - it"s just an impossible game to play good poker consistently - 7 min blinds and fast structure...... if you don"t play a hand in first 30 mins, you are already getting close to an M of less than 10. It"s just nice to be able to watch the live commentary, and to hear critique of your own hands occasionally (especially when you get one right!)