There is no fix range on how much bandwdith or disk space you could be allowed to use. It depends on how good or bad you hosting neigbours are Most of the host use load balacing techniques, but its still wrong to promise something you cant provide. Check out reviews on google as its the best way to judge a web hosting company. But don't trust a review site which has an affiliate link. They just care to make a quick buck.
I think you should choose a hosting company that have good knowledge in providing support for Joomla hosting.
That mean you have decided to go with any one of the above host ? if not. let me know your hosting budget, i will point you to my webhost who operate 24x7 via Live chats emails and by phone support
I've used GoDaddy and Host Gator for my sites. As my GoDaddy hosting expires, I've been migrating to Host Gator, as the fees are cheaper, the service is similiar and the support at Host Gator is great.