Well, among anticonvulsants I've tried Topamax, Zonegran and Lamictal. Topamax can work wonders if you're able to deal with the side effects: depression, loss of appetite and cognitive deficiency among the foremost. Some people don't have bad reactions to the drug and it especially varies based on your dosage (one person recently complained here that 50 mg of topamax was too incapacitating; I was fine up to around 125 mg). I'm now on zonegran, a similar anticonvulsant that has milder cognitive side effects. And we're trying to transition to put some of the maintence load on Lamictal, which is much lighter on the side effects. I'm sure there are people here that will tell you differently, but from my limited experience I think that anticonvulsants are the best first option.
Then there are the tricyclic antidepressants like nortriptyline or amitriptyline which can be particularly good if you're experiencing depression or sleep problems with your migraines. I've tried both that I listed to no avail, but, again, many people have found great relief using them. Side effects are similar to many newer antidepressants (weight gain, sexual side effects, lethargy) but with some additional cognitive effects.
Another one I recommend thinking about is depakote (valproic acid). I had a big problem with excessive sedation when I was on depakote (I couldn't sleep less than ~15 hrs/night), but it's a highly regarded migraine drug.
Hmmm, what else? There's neurontin (gabapentin). It's virtues are discussed in the gabapentin vs. topamax thread on this forum. There really are a whole host of others: Ca+ channel blockers, beta blockers; I keep hearing about Keppra in another migraine community I'm involved with. While your doc will do his/her best to match your symptoms with a drug, you really have to be prepared for the very possible possibility that you'll have to try several before you get it right. Do some reading on preventative medications: wikipedia is a good source of information, http://www.achenet.org/prevention/brochure/drugs.php, http://www.migraines.org/treatment/treatctm.htm#I, etc. Good luck and please keep in mind I'm not a medical professional, just someone who has dealt with migraines for years and done a bit of research.