Custom maps: The best resource I know of is hl2world.com.... not exactly the most mature or friendliest place to hang around, but go into the community releases for a lot of good stuff
Also hl2files.com is good
(note NEVER get map packs... Sure it may seem simple, but sometimes they aren't the latest version and thus that's just wasted bandiwith to download those obsolete maps... for example hl2files has a map pack and when I saw it I got like o.O because so many maps already had one or even two new versions out by the time they got the pack out.)
cl_showfps 1
net_graph 3
(most people prefer the netgraph, i prefer showfps due to its simplicity
)