Which low powered device for server?

[T-Keith]

I have an old "server" running Ubuntu functioning as a Web server with Apache and mysql and phpbb. It is an old pentium 3 and uses about 35 watts in average use. I want to upgrade to something more efficient in space and power, but don't want to spend a lot of money on it. It would be great to use something I have laying around as well. What do you guys think would be my best bet?

Here are my current options:

Cr48 chromebook. Too slow for normal use now. I've read getting Ubuntu to run is difficult.

Android phone running Ubuntu? I have a Droid incredible and Galaxy nexus. Will Ubuntu run on either if these?

Buy a raspberry pi or similar? I'd rather have something standalone that doesn't require a lot of tinkering. Any options here?

I'd love something super low power with wifi that I can just plug in anywhere out of the way. Is there another option that I'm missing?

[Iowan]

I have a Beaglebone Black set up w/ Ubuntu and a LAMP server. Can't say I've done much with it yet, though...

[CaptainMark]

I have 2 raspberry pis one running as a web server and I can tell you they are incredible, absolutely silent and so inexpensive. If its a personal use only webserver I'd say g go for that option, if it's for hosting anything more than that or something you want others to access as well I'd say the RPi is probably not powerful enough so choose another option, it can be a bit slow sometimes and whilst I'm fine with that others might not be so forgiving.

[Thee]

I was also thinking of putting up my own server using the Rpi to serve as a mail server and web server with static pages, as I read on the net, it should work great for that.
It really is the best solution if it can work for what you need. No fans, very small and draws like ~5W of power.

[T-Keith]

Well it's a small website, but other people do use it. How slow are we talking? Is it as fast as a pentium 3 600mhz? Because that is working now. Looks like it would be about $50 for a pi and an SD card. I guess that would work, but would my other options work better for less money?

[CaptainMark]

Rpi default is 700mhz but can be easily overclocked to 1000mhz using the incuded tools and stays quite stable, just draws on a little more power

[Thee]

Well, its an ARM processor, so it's not as quite as powerful as the desktop one, but it should handle your needs.
On the other hand if your needs grow a more powerful server will probably be needed but that equals more money and it will draw more power.

You will have to decide what you need, cheap solution or powerful solution.