I was just wandering around near the imperial city when i seen a body floating in a lake. As i got closer i seen it was a horribly decayed corpse with a love letter to someone on it. Can't remember the dudes name but nothing popped up in my journal so wondering if it's quest related? or just for show.

Good roleplaying opportunity.

If its a lake near a fort close to wye, then I don't think so.
I remember checking out something like what you posted ages ago, and I'm sure its just an easter egg or bit of lore.

This.

Not quest related.

Yeah, it's just an easter egg. A funny little something the developers put in.

Its an Easter egg.
I'm right in believing his name was Nath Dyer? http://www.uesp.net/wiki/Oblivion:Easter_Eggs#Nath_Dyer