If you want something managed slightly while not costing a complete fortune, I would have to recomend
www.fastservers.netThe thing is, if you need to manage a lot of it yourself, you need a control panel, which lets you admin the server from a web browser and GUI anywhere you are. They use WHM/cPanel.
ANyway, their base server with cpanel is 150/month, but adding the control panel will put you at about 180/month. But, having worked with them and owning many servers with them I can say if you do need help or have questions they are amazing.
There is ALWAYS someone that answers the phone, they repsond to support tickets in less than 10 minutes every time I've had questions, and heck, even on Christmas day I had a problem and they were right there to help. So, the little extra you pay may be worth the piece of mind knowing your site will be in good hands.
If you are a bit tighter on a budget, you may want to look at
www.rackshack.net. Plans starting from 109/month.. but mind you, it will be probably a slower server and from what I've heard the support is good when it is good, and really bad when it is bad.
Another one people use is
www.nocster.com They call these managed, but haven't heard anything about how good or bad this really is. I have heard their network will have some downtime, and for their plans you get very low end servers. But for a cheap price.
There are a lot out there, but as always, "you get what you pay for" really does apply. If you are running a very busy threads site, a celeron 1ghz server with 256mb of ram for 99 bucks a month probably isn't going to be your best bet since with dynamic sites you really need quite a bit of CPU and RAM to have it run effectively.
