Anyone with steam should turn on the beta in the settings, they're testing out a
new UI and it looks great!
Store front with new who-bought-what list:
Game page with who-owns-this list:
Game Library page, you can also view in list or grid:
It's a big improvement, I'd still like playlists for games (EDIT: turns out you can do that!) but this is a great step forward.
EDIT: also
Serious Sam HD is on sale, half price (£5.99) until March 2nd. It's a fun game and it supports 16 player co-op too!