I have 48gb (6x8gb) in my x58 rig that I rarely use and just sold off the 24gb (6x4gb) I took out of it. At one time I had about thirty sticks of ram laying around because when it went on sale at a really low price, I bought it.
As soon as the 8gb sticks drop again, I'll probably pick up another 48GB (6x8gb) to split between my server and HTPC just because. That will replace the 2x4gb in the server (only 2 slots ) and 4x4gb in the HTPC. All my machines will have 8gb sticks, including my laptop. Why? Because WHY NOT!
Especially for a HTPC, make a ramdisk and store image cache in ramdisk, VERY fast.