What Cap'n Desslock said is true, cheap stuff isn't going to help. However, using some of the higher-end modellers can get you most of the way to where you want to be. Of course, everyone is right, if you are able to play loud then tubes in proper amps are the way to go, but compromise doesn't have to mean shoddy sound either.
Try looking at Line 6 stuff, but NOT their amps (I've tried their non-valve amps and they sound awful). I'm talking things like the Pod series etc. All my stuff is recorded through a Pod XT and, if I may say, they don't sound too bad:
http://soundclick.com/share?songid=7881278I used to record with my Bronze series Warlock that has a Nailbomb in it, and switching over to an NJ series with the Nailbomb had a massively noticeable effect. If you can squeeze double the money though, look at the Fractal Audio Axe FX, as it's the most amazing sounding Amp emulation tool out there. Everyone who has tried it says that, more than anything, it
feels like playing a tube amp. If I had the money, I would sooner invest in an Axe FX than an actual amp, because of the variety of sounds and its versatility. You can go straight into it at home on your desk through some speakers, direct in to your computer, or through a PA live, and it sounds great through all of them.
My $0.02 :D