As others have said, max out the 401k. One exception being if your 401k has ridiculous fees, then it's harder to make that decision.
To truly answer Roth vs Traditional, we'd have to know your tax bracket now vs how much you expect to withdraw in retirement. I'd wager though that at a 75% saving rate, you're making good money---just based on the information given, I'd say traditional to lower your taxes now vs later. I'm thinking you're in 25% or higher bracket, yes? Not that it's impossible to be saving that much while making only in the 15% bracket, but I'm just looking at probabilities here.