In gen I, I used to just nickname Pokemon their names but not in all caps (ie ABRA->Abra). Then I went through a weeaboo phase and nicknamed everything their Japanese name in gen II (ie Xatu -> Neiteio, I think). In gen III, I was still pretty weeaboo and I was mashing Japanese words together to make something nice sounding that almost had meaning to it (ie Flygon -> Ryuuka [ryuu=dragon]). By gen IV, I just named stuff whatever I wanted. Named after fandom characters, named something that made a pun, and so on. In HG, I ended up naming everything after the French name of something in its evolutionary line because I think the French names are awesome. :D In gen V, it was mostly back to fandom names and names based off elements and the like.
I love love love nicknaming and I love getting nicknamed pokemon in trades, too, no matter how ridiculous the name. ♥