The last gun I "bought" was a custom AR15 I put together at the height of the Obama scare. It took awhile to get everything together. This is my first AR and I've REALLY enjoyed every aspect of my AR project - from researching the various components that went into it, figuring out what I like and didn't like, and creating my wish list of stuff to get at a later date. I've got a fair amount of stuff left over, that I imagine will someday become a second AR!
As far as a gun that I bought whole, as opposed to assembled, it was a Glock 21SF with the tritium night sights.