Reliability and speed of access
This is very important. A site that is frequently down will lose you lot of visitors. If someone finds your site on the search engine, and he tries to access it but find that it is down, you will lose that potential customer. Snail access is also very annoying for visitors.
Not only should the web host be reliable and fast, it should guarantee its uptime (The time when it will be available on the internet). Look for a minimum uptime of 99%. too low - it really should be 99.5% or higher. The host should provide some sort of refund if it falls below that figure. Note though that guarantees are often hard to enforce from your end - the host usually requires all sorts of documentation.
However, without that guarantee, the web host will have little incentive to ensure that its servers are running all the time.
HOST MONSTER is extremely reliable and also very fast.
The up time at HOST MONSTER is 99.9%
Which as you would agree is pretty much all the time.