1) JC Denton (From Deus Ex) - Speaks with that low pitched, not caring tone and comes out with some very interesting lines if you give him the chance to. Could come out with some humourous lines too. And Augmentations... don't you just wish that Augs were out now? Such a cool character.
2) Master Chief (From Halo) - Sounds like Tom Hanks on a bad day. Doesn't talk a great deal, great with any weapon, pilot with any vehicle
3) Jock (From Deus Ex) - I don't know why, but I just like this guy. A guy you can depend on.
4) Paul Denton (From Deus Ex) - Everybody likes JC's brother too. An augmented agent with morales.
5) Cortana (From Halo) - I love it when she gets pissed at 343 Guilty Spark. And its funn ywhen she teleports Master Chief upside down

Not a outstanding character, but she really adds to the feel of Halo (as every futuristic outside earth story has a female AI construct in it)
As for Abe? Not because he's in my top 5 (all I can be bothered to do) doesn't mean i don't like him. However, Munch's Oddysee had too much cartoony comedy in it, and after all Abe had been through in his previous two adventures, you would have thought that jumping in a big well would have been no problem for him.... but he was scared! I much prefered his poetic rhyming lines in Abe's Oddysee over the silly cartoon humour.