There are a couple options for working on your timing. I totally agree. A metronome is a great thing to have, but it doesn't replace an actual rhythm section backing you. Here's a couple things that might work, one cheap and one that will cost you:

There are alot of "Jam Tracks" out there, that have different styles, some even different songs, where the guitar is missing from the track. If you go to Musiciansfriend.com you can find blues, rock, country and I believe Jazz there. Also, there's a site called jamtrax.com that has different songs/styles. You might have seen them advertised in GuitarOne Magazine. Anyway, they have all kinds of different songs/artists. They break the song down note for note, which really doesn't help you learn, but they do have backing tracks for everything which is nice. I'm not sure what either of these options cost, but I'd be willing to bet they're at least $20 a piece.

The second option, and one I use to use quite frequently when I was first learning, is record your own rhythm tracks on something like a cassette and do some leads with it. Start of with something like a twelve bar blues rhythm, in different key and in different tempos and have fun with it. After you get comfortable with that, then start recording rhythm sections from songs you like to play. It doesn't make up for drums/bass, but your timing will probably increase.

I've been playing in bands for years, and sometime I even get off on my timing. Sometimes it's because I can't hear myself, sometimes it's because the bass or drums start lagging and I'm still playing regular tempo and sometimes the singer f#$ks up a verse and throws me off. You'll learn to use all those as cues to keep your timing on in good time.