You're off to a good start. The XDs are great pistols - I have a .40 and a .45, and the only problem I've ever had with either was that the earlier model XDs have had some finish problems, and that is apparent with my XD40. I've tried the Glock, I've tried the SigPro series.. it was the XD which convinced me that there was merit in these polymer framed pistols.
Don't let anyone give you crap about having bought a DPMS. They're good rifles. The first AR I bought was a DPMS A-15 16" carbine. Only gripes I had were Loc-Tite on the extension tube and end plate, and the DPMS "snow guard" handguards, although the latter never proved to be any real issue. People can whine to me all day long that it has the chrome moly barrel, no M4 feed ramps, an improperly staked gas key, etc, etc, etc. I've never had a problem with it feeding, haven't had the gas key come loose, and I can hang with the Colt/Noveske/LMT shooters just fine. I still have it and shoot it, even though I just recently did another 16" AR build.
Don't really know what you're looking to add. Personally, I'd say you need a .22... Ruger 10/22 is a good way to go, as is a Henry lever action. And a Mosin Nagant or two (or three, or four.. I swear, those things have a way of multiplying). Without any bubba jobs being done to it, of course.