If you have a NAS, TwonkyMedia is/was excellent at streaming photos and videos to your PS3 and other devices. I say 'was' because they no longer support installation of the software onto many NASs and so it can get a little involved.
Installing Linux on the PS3 is pretty painless and it's easy to switch back and forth between Linux and the XMB. I recommend Yellow Dog Linux as it seems to use less memory than Ubuntu (important since PS3 only has 256mb main memory), supports the Logitech Bluetooth Mediaboard out of the box, and has a quick way to get back to the XMB. You may want to upgrade your PS3 hard drive if you're thinking about going down that route - 320gb is very inexpensive and easy to upgrade to.