I have a 2008 Trek 7300 that has about 3000 miles on it. The OEM crankset is a low end Shimano M191 that is beginning to showing signs of wear on the middle chain ring. It's not completely shot but doesn't have too much life. The chain rings on this crankset cannot be replaced so I'll have to replace the whole thing. The M191 can be replaced for only about $25 but that one would probably wear out pretty quickly too.
I'd like to upgrade the crankset and keep the rest of the OEM components for now, upgrading them each as they wear out.
I'm am looking to see if anyone has any suggestions.