Also spotted the bit on hosting providers
Microsoft has a datacentre option
There are also other providers, my suggestion would be to:
Find a provider in your country or pretty close, too far and you increase the latency and decrease the user experience
Make sure you pick a provider big enough to have the support you need
Make sure you spec enough resources, the base offerings from the various companies are good to get an idea of price but no where near good enough to handle a company of people
And something that has caused me untold pain over the years, check your printer drivers are terminal server compliant, i personally wont bring a multifunction printer anywhere near a terminal server
Hope this helps, shout if you have any other questions
Cheers
Nev