In Oblivion first person but like others I switch it up every now and then to see my PC

I really liked Modern Warfare 2's third person playlists as a cool way to switch things up every now and then but obviously first person is best, especially since optical attachments are otheewise useless.

Not really on topic but I thought it was awesome that MGS allowed you to first person ADS for extra accuracy. I thought that was a nice little feature that put Metal Gear Online just a bit above other third person multiplayer shooters.