In terms of D&D levels / 4CTF.....
Captain America: Mostly Fighter levels, with some Paladin (minus the Lay on Hands, Cure Disease, and spellcasting ability) and some Hero levels. Total levels: 20, maybe Epic.
Batman: As per Ranger Wickett, and I'd put him at ~18th level.
Daredevil: A mix of Monk, Hero, Specialist, and Fighter (in order from highest to lowest) with the heaviest concentration on Monk by quite a large margin. Total levels: ~12.
Wolverine: A Barbarian-Fighter with Hero levels and a level or two of Frenzied Berserker PrC (MotW). Total levels: ~18.
Spiderman: A Specialist (Journalist, Scientist)-Hero with the highest amount of Hero levels of any of the discussed characters. Maybe with a level of Gadgeteer (Web shooters/fluid, tracers, spider-armour, etc). Total levels: ~18.
Three of the characters are roughly the same level, but I don't think they are at all equal. Spiderman and Batman are both more versatile than Wolverine, but neither of them could stand up to him if a sudden fight broke out. Batman and Spidey could probably escape (if they survive the initial attack), but would have to fight at range to have any chance otherwise.
Cap vs. Batman: Despite what Marvel vs. DC said, I think Cap would win. Especially The Ultimates version of Cap.