How many services do you run on your Raspberry Pi?

Hi guys... I am trying to make a Raspberry Pi base for a smart house. The question is, how many services can I run on a single Pi? I am thinking running XBMC on the front, for all those media consumption needs, and on the background  a webcam motion detection software for basic security, some sensors (temperature, humidity), arduinos, maybe a simple family web and mail server. Can it all run on Rasberry Pi at the same time? Of course, I am counting on Raspberry Pi being overclocked, with a decent memory card...

It does not really matter how many services you run, the question is more WHICH ones you run.

Generally speaking, text based services don't need a lot of resources. By that I mean things like an IRC server, Mail server, Web server (as long as you're not running Apache...), FTP, Sensors, etc. etc.

However picture and/or video based services are (especially for these low-powered ARM chips) really resource-hungry. (XBMC, Webcams,...)

Hope that helps!

So.. if I understand it correctly, if change the webcam motion sensing to arduino ultra-sound module, RPi should be enough for all my uses... cool. Especially, since 1080p video on RPi is decoded on a separate chip...