Looking for some good novels that have a similar feel to them as Mass Effect. I've read the ME novels already... looking for something with a similar amount of lore and ancient history as ME offers. 
 
Also, I love ship life. So stories with emphasis on isolation on a space ship doing epic quest are interesting (have read the 2001 series)

Old mans war reminded me of mass effect a lot. Quite a bit of ship life as well as kicking alien ass.

Man can't we get some more suggestions in here? I've read the ME books too and I'm looking for what this guy is talking about

Try the Starship series by Mike Resnick. Its just what you're looking for.

"The Forever War" - Haldenman, has some hard-scifi and deals with time dilation of travelling near speed of light, and very much the "war, war never changes" theme.  Haldenman is a purple heart vietnam vet and that comes thru in the story.
"Ringworld" - Larry Niven, actually has a bunch of hard-scifi series and books and built one continuous universe setting with a bunch of books and shorts set in it
I don't know, Starship Troopers? 
Poul Anderson  
On the more trashy/action-y side -
Mayne Ian Douglas's "Star Carrier" stuff (haven't read it) 
Anything David Drake - "Hammer's Slammers", "In the Stormy Red Sky"
 
Let me know if you find anything good.  Also up for some good scifi.