Don't know about the keyring, I'll look into it when I have time. Definitely download all the updates. There should be a bunch when you first install and then you'll get them more gradually. The cool thing is you won't need to reboot after updates unless there is a kernel update.
Homemade Intel Dual-core 3.4 gHz, 4 gigs ram, EVGA GeForce GT 430
Mint 14, Arch Linux, Fedora 17