All On Syphon Filter

In my opinion most older games have more memorable themes than the newer games.

Possible. Some of the most memorable themes are from the Nintendo era (think of Link's theme for instance).
I don't mean that because of the technology, music is necessarily better today. That's far from it. But composers have better tools today, so although melodies might not have change through times (a good tune is a good tune, whatever how the instruments sound like), but having better tools to make them sound is certainly a plus.