I don't know, I suppose if it means that much to you to get Darkstalkers, go for it, but if Darkstalkers isn't your series of choice and is merely a random blip in your radar (which it seems to be). I'd wait on it, seriously. Part of what I like about collecting is the thrill of the hunt, going out and seeing what is being released into the wild every day, does it need to be sealed mint? not for me, I want games I can play and enjoy. So mint? yes. sealed? nah.
Is it worth it to you to have something that cost you $150 that is a mere blip in your radar that you could likely get for much cheaper someday? I mean I have see Darkstalkers in the wild, it is really not that uncommon, not $150 uncommon.
I'd say go for the Wii, there is some fun stuff on it to enjoy, and you can enjoy with friends. Darkstalkers your shelf gets to enjoy and you get to know that that checkmark cost you $150, when you'll likely see the game for $4.50 in the timeframe of 2 years.
That's just me though.
I guess I also feel the need to point this out:
http://www.digitpress.com/DP/cmf/game.cmf?gameid=27271