There have been a couple different Mini 10 models.
The original Mini 10 (model 1010) had a Z-series CPU, GMA500 graphics, and HDMI out. Discontinued. Has poor IO performance, mostly slow CPUs, and runs OSX and Linux poorly. Avoid this model, unless you know it's what you want.
The Mini 10v (model 1011) had a N200-series CPU, GMA950 graphics, and like most netbooks, VGA out. This is essentially a Mini 9, except the 10v uses a standard laptop drive. Runs any OS well, and is popular among OSX users. Mostly discontinued.
The new Mini 10 (model 1012) has a N400-series, GMA3150 graphics, etc. This is a slightly improved 10v/1011. A high-res screen and HD decoder card are options. Doesn't run OSX as well as the older 10v/1011.
The upcoming 1018 is similar to the 1012. But it has cosmetic changes, switches to DDR3 RAM, and deletes a couple ports. It might have fewer premium options, too.
As for 1GB vs 2GB, you can always upgrade later. I'd recommend 2GB at some point for everyone but the biggest cheapskates.