I use http://www.ontimehosting.com Been with them for over a year and have experience very very little downtime if any. Their located at The Planet Datacentre. Very good prices as well!
We have their 55 GB bandwith with 1200 MB space for somewhere around 15 maybe 17 bucks a month and we're prob going to have to upgrade that plan since we're using so much bandwith!
I presently use Powweb... When you hear the name Powweb, run as far and as fast as you can toward an erupting volcano, because it will be much less painful than your experience at Powweb.
I've been with them for a few years (my own fault), and yes, there have been months where I haven't noticed a glitch and was very happy, but when they go down, they go down. This means that your 24/7 online tech support can't be used because you can't access even the powweb.com website. Not only that, but when they perform their upgrades at Noon time (Imaging that... Upgrades at prime time!?!?!?!?), they never send out emails letting you know that there might be a chance portions of your service may be affected. TERRIBLE!!!! My site doesn't generate money and is more of a social joint for fly fishermen, but they do have tons of sites that rely on a service that is going to generate money for them. They cannot do this when Powweb is down. Ok, I think you get the picture now...
Now, since you've mentioned Ontimehosting.com... I'm actually building a site their right now. I've been extremely happy with the service, and it's a super fast host. I would recommend anyone giving these guys a shot. When my contract with Powweb is over in May, I'll be moving two other sites over to Ontime hosting.