Basically there are 2 kinds of mics (please dont correct me, i know there are more I just cant be assed going into too much detail)
the first kind is Condensor Microphones - these are used in studios or in live sound where good quality is required ...they are very delicate and require care when handled.
the second kind of mic is designed for amature use (or where it doesnt matter if the mic gets dropped, put inside a kick drum kit etc. this is a dynamic mic.
as a general rule you get what you pay for and dynamic mics are bottom of the barrel, not to diss the 57, 58 and 59 theyre great when used creatively but there are better options out there, BUT if you really just want something cheap that you dont have to worry about damaging then gor for a 59 (virtually identicl to the 58) the 57 is nicer with snares (under) and guitar stacks when there are no condensors available.
you say your budget is £100 so I'd say your best options are (give or take £25 each way) a sweet SE Electronics mic, a lovely Rhode or a trusty AKG Shure. (if you can track one down near you you might also try and get hold of a Joe Meek mic or an MXL.)
Avoid Samson mics at all costs.
The only trouble with condersor mics is they need +64v so make sure your able to use it before you buy, but being that you already said your getting an external soundcard that shouldnt be a problem ..most ext soundcards have mic inputs (64v) and if sor some reason it doesnt you can get around the problem by buying a DIbox and using that to power is.
