My advice would be a 5/8 ROUNDPOINT hollowground blade. But, one caveat-make sure you buy a blade that has been prepared by someone of known experience. A "honemeister" if you may.

NOTHING- and I mean NOTHING is more frustrating than taking on a new physical challenge- LIKE PLACING A WICKED SHARP BLADE against you face. AND not having an appropriately prepared razor. Razor sharp doesn't necessarily sharp enough to shave with.

As your skill level gets established and you develop some muscle memory and the basic principles of Str8 shaving-you may decide to try different size and grind blades. But you must first walk before you run. This site is a wealth of information as well as Lynn's DVD on Str8 razor shaving.

Patience and practice-along with a true shave ready razor will allow you to establish a set of habits that you can build on. And then of course you'll spend tons of loot and suffer RAZOR ACQUISITION DISORDER like of the rest of us.

and remember-ASK questions.