I have been playing at party poker for a long time now having good results. I was thinking aobut trying a new site. Which ones have the best sign up promos now?

Hollywood Poker (Pokerroom skin) is giving 500% bonus
for first signup.

If you play high enough limits it's easy to clear too.

Can you get that if you already play at FCP ?

Yep.

Martins Poker has a 600 Euro 100% bonus that clears at 5x

those are the largest bonuses (also Full Tilt - up to $600), but the quality of a bonus is better determined by the clearance rate than by the size.

for instance, you can do either a $1000 hollywood bonus which might take 100 hours, or you can do 4 $250 smaller bonuses that take 20 hours each.
those numbers are made up - just an example.

for bonus clearing rates, check out
www.bonuswhores.com

also check out
www.pokersourceonline.com
this site gives you a bunch of bonuses that you can add on to the site's normal bonuses. they offer you the same bonuses as the sites, and also give you points for signing up. you get 6000-9000 for each site, and you can redeem 10000 points for $100. good deal.
if you do, please use my referral:
goodmanpoker

and i'd be happy to give you some advice or walk you through your first site or two, since the site can be a bit confusing. just send me a PM if you're interested.

cheers,
daniel

Martins Poker is the best bonus going right now.

Look at the BW forums theres an 8 page disscusion about it.

Well if you havn't done many of these Martin's may be a bit much to start with.

BW 101 is a good place to start.