I've used a number of these with different providers over the years but now have a business package with Evohosting that I've been very happy with for the past few years - it's basically a shared hosting package with addon domains and a few other bits and pieces (SSH access, email accounds etc.). It's based on C-Panel so is super easy to use (I tend to get clients to buy their own domains and just setup an addon domain in C-Panel and then change the name servers in their domain control panel to mine) and I find it great for hosting all my basic sites (i.e. WP, Joomla, static and non-ecommerce/high traffic) and those where clients don't require their own control panel.
Costs vary but the support has always been good (email only), they get back to you pretty much immediately and even helped clear out junk when I was near quota...
:D