miredo - An interesting site by someone who's really into beatmania IIDX.
LainNet - spaztron64's personal site.
-Imageboards-
Heyuri - the place to be. (NOTE: Very much on the "so NSFW, it's practically offensive" side to certain groups of people. Tread with caution.)
Nashi Kouen - a pearry nice site. Basically kid-friendly Heyuri.
-Chatrooms-
Gikopoi - The only site where an indonesian NEET makes a british crackhead literally pass out in the middle of doing pushups.
MelonLand Forums - A cozy little forum made by a netizen, for the netizens. (NOTE: Closed every Monday, as per Melonking tradition.)
Agora Road's Mac Cafe - The Internet's best kept secret.
Comfy Box - A forum dedicated to preservation, among other things.