This is always a loaded question. What works for me may not work for you. The host for me is likely to not be the host for you. In order to answer this, you need to be quite a bit more in depth. Some basics
Look for a host central to you and your clients
Look for a host that has qualified support. Ask questions you know the answer to. Be reasonable, but fair. Remember, you're not a client, but a potential one.
Look for a host that's been around a while
Look for a host offering the environment you need