I've worked with poplar, balsa, basswood, oak(mistake) and pine.  But i'm wondering if anyone here uses any sort of a synthetic material?

Yes, I have used Sintra to make a few lures. The stuff floats, its easy to carve with standard woodworking tools, no grain to deal with, will not absorb water, holds hardware very well, and does not require sealing llike wood.It is however fairly expensive and you can not just go to the local home center and find it, at least not where I live.

I can't remember the name right now, but there is a material used for signs that has the same properties. They'll even send over a sample plank if you ask, just can't remember whom to ask!

DP, Sintra is used primarly for signs. The local sign shop owner is a friend and he gave me some scraps to try but the stuff is expensive. It should be great for swimbaits or musky gliders because there is no weight variables like wood, once you arrive at the correct balance it would be vary repeatable. One other advantage is when drilling it the drill does not chase the grain like wood.

I can't remember the name right now, but there is a material used for signs that has the same properties. They'll even send over a sample plank if you ask, just can't remember whom to ask!

Is this it?

http://www.signfoam.com/

Yep, I think that's it!

Yeah, the stuff is high, but then again, what isn't

Got some of that stuff too from the same sign shop. Carves and sands easily but does not have a smooth surface and does not hold hardware, either screwed in or glued in. For an outdoor sign veiwed from a distance it looks and works great but I think you would be wasting your time making baits with it.

If you have a sign shop in your area check and see if they have any scrap pieces and give it a try you might like it a lot better than I did.

There is a guy over at tackleunderground that is carving his jointed swimbaits out of PVC, but I don't have any details.  I wish I did.

Thanks for the input guys.  I'll probably just stick to wood for now.  I need to get that right first before I try something new.