Sorry for the slow response on this--
I currently have 3 FD lenses, two of which see regular use. Here's my current lineup:
Canon 50mm f/1.4 (bayonet)
Canon 24mm f/2
Vivitar (Komine) 24mm f/2
The two Canons comprise my daily, around town kit. While very compact, they are quite dense, so I'm not sure if they'll make my travel kit.
I originally wasn't planning on picking up either of the 24mm lenses. I found the Vivitar in almost brand-new condition in original box for a steal. A few days later, I found the Canon and got a great deal on it because it has some slight, non-IQ-affecting scratches on the coating of the front element (in areas outside of the sensor coverage anyway).
Optically, the Canon 24mm is great, even wide open, though it does suffer from some CA as you'd expect from a wide angle lens. By comparison, the Vivitar has a soft, diffuse effect wide open (might be good for retro-looking portraits), but is sharp stopped down to around f/4.
I also have a Hexanon AR 40 f/1.8, which I use with my Panasonic 4/3s adapter. It's a great, sharp lens, and I use it about as much as the FD 50 f/1.4. My two minor complaints with the Hexanon are, first, that you can't set the aperture to half-stops, so in application, it's a stop slower than the FD 50 because I can shoot with great results at f/2 on the FD while I have stop down to f/2.8 on the Hexanon to get similar results. The other concern is that at f/2.8 (the next notch down from wide open), the aperture blades have a funky shape (see
HERE), which makes for some funky bokeh when there are light sources in the background. The notches go mostly away at f/4 (
HERE) Again, it's a great and compact lens, and probably will be in my travel kit because of its image quality and compactness.