Don't you love our curse? No matter how good my system sounds I'm always careful to never let my wonderful (and indulgent) wife know that I'm completely satisfied. Terrible, I know.
I had an Exact cart which was my first 'good' cartridge and it was an 'aha' moment because I finally understood what all the fuss was about regarding vinyl. Then I moved on to a Clearaudio Maestro v.2 and it was a great upgrade. After another year or so my curiosity about the MC mystique compelled me to upgrade again. I considered many options, some costing over $3k, but I settled on the somewhat overlooked Rega
Apheta v.2. Nice thing about a Rega cart is that it can be installed with a greater level of confidence with its three point mounting. I LOVE this cart. It's very detailed, energetic, dynamic and just plain fun.
Also keep an eye out for an ultrasonic record cleaner like the AudioDesk Systeme. If you find a good used one you may find it as much of an upgrade as a new cartridge.