I think that you can combine both of them. For us we wanted a huge winter Wonderland with all the blues and the light Blues in The Light blues and Silvers and then we also wanted a rustic theme. so in turn now we are going with an Alberta winter wedding. Which is going over very well for it all
I would pick your venue first and then decide which style to go with. My FH and I looked at a vineyard (more rustic) and then a hotel/casino (more modern). We ended up choosing the casino, so we went with the modern look.