I think gabapentin helps out okay for anxiety. It's no where near as good as benzo's even the shitty ones like Librium, but it's definately better than something like buspirone, at least in my experience. I found that with gabapentin, the best way to get consistant anxiety relief is to keep your dosage low, I would say no more than 600 mg a day. If you take very high ammounts of gabapentin, the BA strangely goes down in a linear fashion, so in a sense it's just wasting it.
one thing that should be mentioned though, is that gabapentin effects people very differently. When I first got prescribed neurontin, I thought it was a miracle drug, similar to a mix of xanax and dextroamphetamine. I quit it for a few months, and when I started on it again, it effected me totally differently. Now i find the effects more similair to a body buzz similair to alchohol, with a mental high that is similar to marijuana, which is really unpleasant to me. Some people find Gabapentin to be very stimulating too, which may not work out too great if your using it for anxiety.