Okay, I am in your boat, and I will suggest that narrowing down your collection may be advantageous. I was in the habit of buying everything under the sun....new, discounted, interesting, not so interesting....even purile, and occasionally gold. At some point, I realized I was in the same boat as you: full time career, family life, other demands, and somehow I still managed about three sessions of gaming every two weeks, but my collection would clearly require a session a day to be properly utilized.
I basically consolidated what I owned, looking hard at things which I might have a fondness for (Book of Vile Darkness) vs. things I might actually use (core rulebooks), things which had sat unused on the shelf for two years or more (Blue Planet), things which I ran ten years ago but would never run again (spelljammer). Modules suffered a lot in this exodus, since I almost never run published scenarios (exception being the Dungeon Crawl Classics and modules specific to campaigns I like, such as Eberron and Arcana Unearthed).
It was a hard process, but I really felt better culling my collection down to an actual, useful set of materials. I kept a few things in mind, including my gaming buddies who have been years' long veterans, but own maybe 5-6 books, as well as considering game books like I do novels: once read, will you ever read it again? Never read.....will it ever? So some rules of thumb:
1. Apply the "one year" rule (or "two year" if you have a slow gaming cycle) to all books....ask yourself if you've read or used that book in the last year. If not, then why? I, for example, have not used Unknown Armies in three years.....but suspect I will one day get around to running it again. I might not think so in another five years, but what the hey.
2. The "Redundancy test." Too many books on the same subject. I got rid of a lot of "crunchy yet less filling" D20 books that way. Assume that you'll see 5, maybe 10 prestige classes in use in a year-long campaign. Figure half of them will be from the core rulebook, leaving maybe 5 to come from other sources. Now, assuming you game D20 for ten straight years....you might possibly (high end estimate) end up needing 50 weird prestige classes in a decade of gaming. That means that if you've got one, maybe two books full of prestige classes....you're covered. Pick out your favorites, sell the rest. Also works for other subjects, such as feats, airships, dungeon delving guides, and class/race books. Keep in mind that everything you really need is in the core rulebook and your imagination; the rest is just fluff.
3. The "coolness factor." Did you get a book just because it was cool? Shame shame! I did that all the time.....and almost always regretted it. Games which are uber-cool musts till also be useful, no matter what. Look hard at these books, and ask yourself, "Am I a poser for game X? Will I ever really run this super cool campaign.....or do I just like the art?" Sell it to someone else on ebay who's looking for cool at a discount.
4. The "brand X sucks" factor. Dump and avoid anything from companies with a tried and true track record of crap. Pick up FFE book. Look at it, smack yourself with the book, and say, "What was I thinking?!?!"
5. The "longevity" factor. Some games are built to last, and some aren't. Most FGU games, for example, should have had expiration dates sometime around 1992-93. Call of Cthulhu, however, is a game built to last the ages. Older games should be regarded carefully for the usefulness/nostalgia factor, and their potential for gaming in the sophisticated 21st century may have stagnated. Just check out Cyberpunk 2020 for a sample of what I mean.
6. The "nostalgia" factor. Sometimes, the fond memories are worth holding on to a book for (I have a complete Tunnels & Trolls collection that's filled with memories of youth) but such games can easily go in to a box, hidden away, where they will not distract from modern pursuits. In fact, even current games could get boxed up like that, to keep from distracting you from whatever specific game you should be focusing on.
I have limited my own collection to Call of Cthulhu, Star Trek, Star Wars, the core Wizards D&D books and a few supplements, the Malhavoc/Arcana Unearthed stuff, Goodman Games, GURPS, Savage Worlds, Gamma World, KULT, Unknown Armies and Ravenloft. I only use GURPS and D&D right now.....but every couple of months my group will switch off for three weeks for a mini-campaign in some other system, giving us a break from the regular campaign in the big two. It seems to work doing this, and gives other games such as Savage World and KULT some extra time.
BTW: I do not have kids, so I can effectively double my "list of things I can
concentrate and work on" over your own list, sorry!
Good luck!
