aside from the plain coolness factor, you just get a much better shave with a straight razor. with a mach-3, by afternoon i already have shadow, but a good shave with a straight razor lasts much longer - often ill just shave every 2 days.
you should stay away from *new* razors, and never buy anything thats stainless steel - it wont hold an edge. you can get some nice razors on ebay or if you look around in pawn shops, make sure the edge has no nicks and is straight. when buying, pitting is not good, but staining or even slight surface rust is perfectly fine. you shouldnt be paying more than $3-10 bucks for a razor: remember you are buying this for shaving, not to mount on a wall. same applies as for knives: boker, henckels, solingen steel etc. are good, sheffield steel is usually the best. nicks/chips can be ground out but it is not worth the trouble - stay away from them, and do
not try shaving with a nicked razor if you value your face.
a badger hair brush will probably cost you a lot more than the razor, and isnt 'necessary', but it certainly adds to the experience and
everyone should use one - even those who shave with disposable razors.
once you have *cough* practiced on yourself - and are confident you can do so safely - offer to shave your wife's or g/f's legs for her

trust me shell be
very impressed.
i actually have a question myself:
has anyone who shaves with a straigt razor tried one of the pocketknife/straight razor combos? i believe boker and some other manufacturers make them... however ive only seen them online and they seem like they are flat ground from stainless steel - both indicators that they are useless as anything but novelty items.
cheers,
-gabriel