Best site for simple hosting (php/mysql/mail/smtp server/ multiple domains):
these guys are not too expensive, have GREAT support; what is really cool about them is that they allow multiple domains to be aliased into their accounts. Right now, on one of my accounts, I have 5 domains... It cost $1 per month to add a domain alias- all I had to do was add a .htaccess rule to the site, and I had a new domain. This is cool.
If you want to have more control, and have your own box, here in Austin, strong suggestion for:
They charge a low fee for a 1U rack server, and then have a very modest varible cost for the amount of traffic that your box moves across their network. What is cool about this is you can have your own box, and do whatever you want (versus just having one login) for a really, really cheap price. I would not host videos off of this service, but if all you are doing is apps that are creating html (not big files) and you have your own box (server or 1U server) this is a great option.
In fact, with the ability to buy a box through Dell on credit (it is pretty easy to get up to a $5,000 credit line through their small business group, you could really do some interesting things with this type of service- and end up buying the box... (there are other cheap full box solutions... but given that these guys are local, and they have been very helpful, I really like what they have done for my business.)
The places that I would stay away from:
Not bad guys, just not as quick as modwest about support; lots of times their smtp servers get black listed due to use by spammers (which they do not allow... but happens anyway)
They're evil. OK... just kidding. If you are looking at them, stop.... not reliable enough to depend on. They were great when they started (years ago) but too much of a pain to deal with... so I stopped.
They are expensive but worth it. This is sort of run-you-own-server with training wheels. You get the root password, but they can help you out of most jams. They answer the phone with a live human anytime of the day or night, weekends, holidays whatever, and you can speak to a Level 3 sys admin. If you're serious about running an Internet business, you'll eventually either want to hire you own sys admin and tie him/her to a desk, or go with Rackspace.