Whatever you choose you should enable zram! It's a Linux kernel module so available on all distros. It makes a compressed partition on the ram.
I've had a ThinkPad with 8 GB of ram and it was night and day with zram enabled. Just used the defaults, no more stutter or hanging for minutes. I used Tumbleweed.
UFO 50 is fantastic.
Got a favourite yet? A friend and I have been paying a lot of lord's of disconia and party house most recently.
For anyone not familiar, UFO 50 is an anthology of 50 games in the style of nes/SNES era. It's made by Derek Yu, who made Spelunky before it.
Tons of Hollywood films are shot in Hungary! Dune being one of them, but there's many many more. Cheap extras, cheap studio space and VFX industry.
OpenSUSE Tumbleweed has great KDE implementation. Best I found and stuck to last time I hopped around.
Rolling release yet super stable. Great configuration tools.