Long-time PnP player/DM. Like "20+ years playing Dungeons & Dragons" long-time. I'm a big Forgotten Realms fan, but I'll play any well-done world. I've played in Dragonlance, Dark Sun, and Greyhawk as well, so I know a bit about the last three, and a LOT about FR. What can I say, I love the amount of lore in the FR setting.
I do like to play the optimization game, but only within the framework of the character I'm playing. I'm not the type to build around a specific mechanic (uber-charger, diplomancer, etc.) unless it really makes sense for the character. The WotC CharOp boards were interesting reading to me, but I can't remember anything coming out of there that I'd actually try to sneak past a DM. Spending time on the CO boards also made sure that when I was the DM, I knew what to look for in case someone tried to sneak a CharOp build past me.
When I DM, I'm not the type to do one-shot games. I like really getting into a campaign with a long-term goal, and a villain that the players will (hopefully) remember for years to come. I allow far more books in my campaigns than I disallow, with the exception of third party books. I tend to stay away from those due to personal preference.