Well, let's see: until now I've tried the following (except paypal :p, which is a big NO-NO, at least for me)
1. Ikobo - signed up after my problems with paypal, but I left it to that because they look rather fishy to me - very slow support staff and I spotted several spelling mistakes on the site at the time (they may have been corrected since then). Plus they seem to need a LOAD of documents to raise your transfer limit from 205$ a month. A letter from my bank? COME ON
2. Moneybookers - they also need a lot of stuff sent to them, plus the signup is tedious, I lost a customer because of that...
3. ShareIt - although it has (very) high fees, this is the one I'm using, it's similar to 2Checkout but it doesn't have a setup fee. A big advantage is that customers don't need to sign up to pay, you can simply provide a link for them to go to and pay via CC.
Hope this helps.
Oh, yeah, and also, I found some very disturbing threads regarding iKobo on Sitepoint.com - just do a search on iKobo there - it appears that iKobo pays (or used to pay) people to spam message boards with messages about how good iKobo is.