I started picking up some about a year ago as well, partially to get me a nice repro jacket with patches of my own choice, partially because the era of fifties/sixties/seventies is the most interesting part of military aviation, and partially because the designs appeal (well, that's actually decisive; if it's not attractive, I don't care). And then, it's an old hobby that was expensive when I was 16, but now the availability of patches is endless and quite affordable.
My basic reference is usafpatches.com, secondary is wikipedia for unit histories (lineage, components, aircraft, stations etc).
I'm hardly an expert, a well crafted repro that fits in neatly in the era would do it just as well for me.
A bit off from the usual is always nice.
Main source is ebay, but only prices within reason. Many are like $125 up to $200 when BIN, but will show up every now and then as an auction and can be had for $35, and often not even half of that.
5th Strategic Recon Wing.
http://en.wikipedia.org/wiki/5th_Bomb_Wing
Picked it up because I don't see them often, whereas many patch versions of the 5th Bomb Wing are pretty easy to obtain.
305th Bomb Wing, Hustler era. What can I say. The sexiest bomber ever designed.
319th Bomb Wing. Bought this one for the added upper scroll. Not terribly rare, but unusual enough to appeal.
1st Tactical Recon Sqdn. Part of USAFE for several decades and flew the RF-4C. I was/am a fan of USAFE, though nowadays they're but a shadow of the seventies/eighties. The Alone, Unarmed and Unafraid makes recce a bit more heroic (Alone, Unarmed and Scared Sh*tless was also mentioned when I found some recce info on the internet). This is the early version, the later version is more aggressive but over the top compared to this one.
52nd Fighter Wing (Air Defense), from the sixties. Particular because of the separate lower scroll. Part of USAFE, so I saw their aircraft pretty often. The only Wild Weasel unit in Europe.