It really depends on your site requirements. How many visitors, how big of a website,
and how much resources you need.
DO NOT BUY SHARED HOSTING. You need VPS or Dedicated - those guarantee a
certain amount of resources are allocated for your website. This will guarantee
uptime of 100%.
For corporate, I recommend
hostforweb.com. I was with them for a year. Their
customer service response time is less than 3 minutes. My experience with them
has been absolutely amazing. It's a little more pricey than other VPS hosts, but
that's to pay for the reliable customer service. Theirs are all managed servers,
so you will get 24/7 uptime and round the clock support.
Also, you can check out
webhostingtalk.com - it's a forum to find web host. You
can get more applicable recommendations there.
What's your budget? What are your requirements?