Ok, I'll try not to be jealous and put my online crush aside to give an unbiased response.
DON"T DO IT!!! HE DOESN"T DESERVE YOU!!! YOU"RE BETTER THAN HIM!!! Ahem...um...yeah...
Hehe, just kidding.
Obviously, I can only base my opinion on the information you've provided. The prideful, spiteful person inside me wants to say that I'd never give a guy a second chance. You had something good and you threw it away. Your loss. Unfotunately, life isn't so black and white.
YOu too broke up because you drifted apart, not because by the end of the relationship you were constantly at eachothers throats. You didn't break up because he cheated on you. You guys just drifted apart. It happens, it happens with couples and platonic friends. I would never refuse to redevelop a friendship that ended due to drifting apart, so I would give a lot of thought to the possibility of reigniting a relationship that ended in such a way.
No one is perfect (even me. I know, hard to believe), so I'd like to think that if I ever screwed up royally in a relationship, I'd get a second chance. There are things that are unforgiveable in my mind, like cheating, or violence, but something as innocent as not being ready for a serious commitment...hardly a capital offense.
Ultimately, only you can answer this question. Go with your gut. Yes, you have emotions involved in this decision, recognize them, but do your best not to let them rule your head. Remember all the good times, and remember the bad. Take into consideration why you guys drifted apart. Then, if it feels right, have a heart to heart with this guy and see where he stands. I think you both need to put all your cards on the table. Tell him what you want out of the relationship (serious, long-term, with the intent of settling down).
I can't say that I know you all that well, but by the emails we've shared I can say that you're a great guy, sweet, kind, and genuine. I'd hate to see you get hurt all over again by the same guy, especially if it's for the same reason you broke up the first time. But, life isn't easy, it's a path of lessons that we must learn. If you really, really feel that this is something you want, then go for it. If it doesn't work out again, well, that's life. Yeah, it'll suck, but you'll have a whole new set of good memories to hold on to, and a new lesson learned.
Good luck, and keep us posted.