Generally speaking, a seattube angle of 73 degrees is pretty much what a road racing frame has. You'll see alot of 72.8, 73.4, which are a Mfg's way to pretend they're different. Be real wary of the old "proprietary" geometry story. That usually means your being sold a bill of goods. A slacker angle, less than 73, will be more appropriate to a touring bike. Steeper is time trial bike... I've got a 78 degree TT bike. The slacker your geometry, generally you'll ride more upright. That may be more comfortable, but for me I really like steep seattubes as I've riden TT so much. Head tube angles are about teh same: 73 is standard, slacker than that is touring-type geometry with some noteable exceptions. So... this matters depending on how you ride: race/performance vs. touring/comfort.