If it's a 2009 21" iMac then its maximum memory is 16GB (the 2009 20" iMacs max out at 8GB).That sounds good. I don’t need screaming high end, just a system that can handle current demands. My 2009 does okay with that, but since it maxes out at 8GB of RAM, it won’t be long before that isn’t sufficient. Heck, Chrome eats 8GB of RAM without even trying.
Staying with Mac is my goal because I never want to go back to Windows. Ever.