If you're a Wii only owner and you don't see any possible way to earn enough money for both over the next three months, I would recommend that you wait for C2. While BO may not be bad for the Wii, it's still missing a decent amount of features compared to it's HD counterparts. C2, as far as the Wii goes, will have better graphics, more features, and more single-player replay value. That's by the current look of things though.
Uncharted 2 Machinima Voice Actor. Currently playing Sully and Lazarevic. Add me on PSN if you want to get involved: Geo_Chronic.
Keep playing Goldeneye and wait for Conduit 2. Black Ops has lame single player and no local multiplayer at all on the Wii (and it's still pretty lame on the PS3 with 3 or 4 players because all but 2 maps are way too large for splitscreen). The online is very extensive, but it's not all that much better then GE's online.