What model is your MacBook? Perhaps you want to stick with 10.5 Leopard which works wonderfully even on an 1.6 GHz Atom with 1 GB Ram. Snow Leopard needs at least 2 GB and sometimes is slower than Leopard on older Macs, that was my experience at least.
Now the point is: Upgrade price. I mean, you can easily find a Snow Leopard upgrade disc for $ 29 which works even with Tiger. Instead going Leopard would be more difficult and expensive and personally I would not get too excited about using SL with 1 GB Ram. I have used Tiger on a PowerBook G4 1.5 GHz with 512 MB Ram from over 6 years ago (perhaps 7) and it did not skip a beat.
I hope you take the right decision.