If you had 100$* to spend on video games that you'd have to play on a desert island,** you should probably get Popcap Game's complete collection from Steam. I'm only running this assumption off of two of their games, (Peggle and Plants Vs Zombies), but they are absolutely addictive and can be played for a long time.
Yesterday I stopped playing Plants Vs. Zombies (PVZ), not because I was done, but because I need to do other things with my life. I uninstalled it and deleted all my personal files. I did the exact same thing with Peggle.
It's a good thing I didn't get PVZ on Steam, since they just added achievements, which I can't resist. Some of those things look very tricky.
I think I've figured out a winning strategy: in Night mode, just spamming the free mushrooms will get you through most levels. In harder challenges, the trick is Ice Watermelons. If you have one of those for each row and the floor spikes in the front row, the only thing that can get you are those damn mining zombies.
*Not allowing free games, otherwise you could have all the games you'd ever want forever without spending a dollar.
**The computer, electricity, etc. is included, you nit-pickers.