The n-gage in principle is a good idea. Unfortunately, Nokia's implementation of it was particularly fraught with problems, imo. A few simple chnages and it could be actually a good system...
- discard side-talking (I believe this has been done in the next version)
- move MMC slot to not behind the battery (likewise this)
- rotate screen 90 degrees, and preferably increase its size
- release an SDK to get yourself a potential underground scene
Those 4 (ok, 5 for the resolution increase) things would have made the ngage a great console, I believe. Without them, it falls squarely into mediocre...