In reply to The New NickB:
Get some good training videos as they are boring as sin. Sufferfest (
http://www.thesufferfest.com ) do some good ones that are brutally hard, and actually keep you interested. You will care less about what speed / distance you've done on those and more about just staying on the bike and not collapsing.
Apart from that, it depends how much you want to spend - I spent c. £130 on mine, an elite supercrono elastogel that is (reasonably) quiet as it uses oil and a fan to provide resistance, and I was very happy with it when I was cycling more seriously. You change gears to generate more resistance so it feels more natural, and there is theoretically no upper resistance limit. You could get an all singing / dancing one for £300 if you really wanted.
Stay away from the cheaper magnetic ones and the fan based ones as they either don't provide enough resistance or sound like they are going to take off.
TBH, mine is just gathering dust, where are you based? Could let it go for £80 (if the mrs agrees).