I go with the proven great fighter. Never underestimate the Lion. Lewis survives a rocky moment or two, to hammer out a unanimous decision.
I don't know who would be a favorite, to me it's more a pick'em fight. Lewis had a weak chin and was KO'ed twice by lesser fighters. He wasn't perfect or unbeatable. If he got tagged and went down, he stayed down. Many people think he should have lost to Mercer, (I had it a draw, this was a guy a 40 year old Holmes manhandled). Lennox had two lousy fights against a shot Holyfield who was way past his prime, (being the much bigger, heavier guy, he couldn't stop Evander?). Those fights were awful. He had a lot of other fights where he did not look that good. I just think he was a very vulnerable fighter.
My confidence levels of a Lewis win would be lower based on the version from Rahman 1. Its customary to take the best versions of each fighter in fantasy fights, unless specified otherwise, though. For a fighter so "vulnerable", it is notable that Lewis has arguably the deepest and best win resume over <220lbs punchers in boxing history. Tua is arguably the closest Lewis faced to Ike in both quality and style. Admittedly Ike's feet weren't quite as slow as Tua's, whilst David hit harder. Their fight was close and people scored it both ways. They were on the same level. Lewis wasn't a level above Tua, he was multiple levels above. Lewis beat Tua without breaking sweat, I think its the easiest 12-round distance world title defence I recall watching. Of those that have commented on this thread, you are the most pro Ike/anti Lewis, yet even you don't make Ike favourire. That speaks volumes, imo. Yes, like the majority of others posting in this thread, I'd make Lewis a heavy favourite.