Just keep it. You'll be happy you did. Mine's in the mail and should be here soon. Everyone always says "just wait until this special event, it's only x days away." And then when the upgrade doesn't come (which it never does!), they'll say the same thing again. Instead of waiting for something you have NO idea when is going to happen, just keep it, and enjoy it. This next upgrade isn't going to make a huge difference anyway. I got sick of waiting, purchased when I did, and I'm glad because I know I'll have a great machine regardless, and the majority of people will be sitting in front of old computers saying "only x more days until it comes."
Now I could be wrong, and it could come out soon, but if you're always playing the waiting game, you'll never get what you want. By the time Merom comes out Santa Rosa will be around the corner.