Relocating an old home stereo has already been suggested, but I'd also add a set of moisture proof speakers to keep humidity affecting them.
I've had a gas heater and dehumidifier in the garage for years-mostly because I dislike having the floor sweating and rusting tools, bikes and parts in the garage. Works like a charm even if I have to manually empty it.
Old toothbrushes work like a charm for cleaning parts and chains.
Garage sale pie tins, muffin pans and cookie sheets with tall edges work fantastic for parts cleaning 'bins', and even as shallow organizers in tool chests. I have a few cookie sheets with Oetiker clamps so I can paw through them yet they are still 'organized' in my fastener drawer.
Have a container of Q-tips handy for small cleaning duty. A roll of paper towels and garage rags as well.
When tuning a bike, have a shop fan feeding cool air into the front of the bike. If you don't have a table at the bike's height, use your tie-downs to hang it from the ceiling.
Trawl through craigslist for a cycle lift. Even if it's the hydraulic foot pedal version, it'll save your back several times over.
Use compressed air in nooks and crannies after washing your bike to prevent rusting from standing water. If you want to get particular, use WD-40 sparingly at pivots etc after drying the areas.
I found Jesus. He was behind the sofa the whole time.
1996 M900, "Patience" 2012 GS "Sonar" 2008 Megamoto "Big Blue" 2008 S2R "WTF"