I'd get a few recommendations and go with one of them. At the end of the day the only way of finding out how fast a host is is to try some out over a period of a week say which is a rather tedious way of spending your time.

Can you afford a VPS? That would give you the best guarantee of reasonable performance without having to go for a dedicated server. Otherwise you are on shared hosting. Drupal's built in page caching hugely improves performance but you might want to look at http://drupal.org/project/boost. However once your users are logged in this wouldn't help page loading time.

You will probably have quite a few modules so potentially there is quite a lot of code to parse and compile on each page view. So go with a host that runs an opcode cache - makes a huge difference in this situation.

Strange as it may seem, on shared hosting you will get best performance if your site is reasonably busy. This helps ensure that your code remains in the opcode cache and that queries are present in the MySQL query cache also. I'd recommend our host (www.nethosted.co.uk) wholeheartedly on the basis of their technical support which is outstanding, server performance is usually very good but they've got a new (and excellent) backup system which can put the server into a bit of an iowait situation occasionally. This is fine except if you have a not very busy site (so that stuff is not in the server caches) and a visitor comes along and requests something which is not in Drupal's page cache then all of a sudden you have 3 problems

• Drupal has to do a full boostrap (i.e. load up all the codebase required to serve the page)
• and so PHP has to load all the necessary code files (disk intensive) and compile them (CPU intensive)
• MySQL has to run all the queries (potentially disk intensive)

At the end of the day it's always a trade-off - what you get, what you pay... good hosting package features + good disk space + good bandwidth + good server performance + good support + low cost is what everyone would want..!!

As I say you could do much worse than nethosted and they are upgrading their backup system later in the year so hopefully the iowait issue will be reduced. I'll also check out another host who seemed to offer good performance on their shared hosting.

[update] The other host I was thinking of is www.eukhost.com, used by a friend of mine but seems good combination of value, performance and support.