I've not had a Hughes system since the HN7000 first hit, but I was actually a pretty avid gamer with my 7000. I'm sure not much has changed with Hughes since I had it. Warcraft 3 ROC and TFT worked pretty well, obviously about a 1.5-3 second delay between when you click to move and it actually happens, but overall worked about as well as dial-up did for that game, especially on DOTA. Sometimes during prime-time you'll lag a lot and sometimes disconnect, but rarely. One thing to note about WC3, if you use the matchmaking service you never have to worry about this, but if you play custom games, never ever ever try to host a game. Everyone will lag worse than COD4 on dial-up, lol. Command and Conquer Red Alert 2, Generals, and Tiberium Wars worked ok, similar results as that for Warcraft, however in the game lobby it shows a ping indicator and a lot of the times with you never leaving red, you'll get the boot. City of Heroes doesn't work very well, it's netcode differs from that of WoW, when you start running after a few seconds you start warping around. Diablo II, from what I remember worked ok when I played it on my DW6000, but I did not hardly play enough for it to matter. As the OP said, Planetside, surprisingly works quite well! Also, I have recently played Rockband 2 on the WII at my friends who has a HN9000 and it seemed to work flawlessly, can be a little slow finding bandmates but other then that once in game, worked fine.
The bad part about living in a rural area...Verizon 3G connected through Cradlepoint Router. 1.3Mbps Top Speed.
Desktop Computer: Alienware Area-51 ALX
Laptop: Acer 5570Z
Netbook: Acer Aspire One AO532H