I think he's already watched Cowboy Bebop...

No, maybe you should try out...

Paranoia Agent (I'm doubtful as to whether this suits your style. And you might not like it... I do highly recommend this in general, though. It is a well-executed, professional, brilliantly-thought out piece of work that excels even with a mostly stellar production cast. Please do read up about it and give it a try. It's not that long either; 8 out of 13 eps have been released so far by Anime-Kraze.)

Full Metal Alchemist (I'm not sure whether you can easily get these; now that it's licensed. Might as well. keh.)

Kenran Butoh Sai: The Mars Daybreak (This seems very slightly like Cowboy Bebop, but doesn't have such grand aims. It's just entertainment, but at least the animation is well done. Everything seems to be cliche, but somehow I can overlook that because it's all light-hearted, not serious in the least bit, and just something to relax and watch like Saturday morning cartoons... I keep comparing this to that o.o; Oh, but try avoiding the parts where they say what happened in the previous episode, or what happens in the next episode. THe pronounciation of "The Mars Daybreak" is just... atrocious. I understand the constraints, but they surely can make an effort. It's not so hard to pronounce it... "Za maazu deibureeku" doesn't really cut it.)

Monster (It's still not in the thick of the action, at episode 5. But this is planned to be 72 episodes long... I have read another manga by the creator (Urasawa Naoki) of the manga of this anime, 20th Century Boys. I think you would really like that manga, and I also strongly recommend it to anybody in general. It seriously IS WONDERFUL. I haven't read the Monster manga (this and the 20th Century Boys manga are scanslated online at mangascreener's site, it's a joint project by mangascreener and Band of the Hawks.), but I haven't heard anything bad about it (even from very critical people), and considering how incredibly incredibly impressive 20th Century Boys was, and how many people compare the two, I am sticking on with this to see how good it gets. I can already sense something good happening. Do try this out, I recommend this to you.)

I don't recommend you get Aishiteruze Baby, Kimi ga Nozomu Eien, Gunslinger Girl, Chrno Crusade, Tenjo Tenge, E's Otherwise, Saiyuki, Bakuretsu Tenshi, Tristia of the Deep BLue Sea and others just considering what I think are your preferences. The only way, of course ,is to try. A lot of people wouldn't have recommended some things to me, but because I try them out I discover I like them. Then again I really can't predict what kind of things I like...