A couple of things
I use fasthosts, there telephone support is excellent and they're always able to sort out any problems quickly and efficiently. it's £500 a year.
Charlies comments about google have just put ther fear of God into me, how can they penalise you for running more than one site? I was going to run 200 or so off my account, I'm worried now as my next £500 payment is due any day. helpppp
Avoid like the plague any (so called ) hosting company who have a website taken from templatemonster or any other of these micky mouse template places 99 times out of a 100 they're bedroom operations and notice there's never a telephone number!!!?? and they usually accept payment by paypal - "an absolute giveaway". Exibit A: arsehosting.com sorry rshosting.com
Your hosting has to be 100% reliable, when your site is down, your earnings are down.
BEWARE, over the years I've had nothing but trouble with hosting companies
Do some proper research, call these companies, speak to them, email them, you'll soon get a feel of whether they're genuine and trustworthy or not.