Hosting is very original business that has many peculiarities - I was digging at Joomla Community forum and have found interesting thing about Joomla hosting. First of it was interesting for me because Joomla 1.5 themes are my hobby and I want to know how to choose right hosting. If you want to promote your hosting services at this forum - you find there some rules that will be useful for you. As for rest companies and details I believe that you must read some additional information about some tricks of hosting services - all these things with prices, bandwidth and unlimited plans. But most important - even if you have bought great example from Joomla 1.5 templates check out that your hosting provider supports Joomla. It may sounds funny but it is true. Keep up!