I'm really trying to work in unusual combat challenges to keep combat fresh--plus, it's a swashbuckly game, so terrain becomes important.
The first game I had two big combat sequences. The first was a port/docks/wharf area, with lots of narrow wooden docks, floating boats, and large aquatic patches to break up the terrain. Everyone was still learning the game, so there was some bottle-necking.
The second encounter--nothing special, an alley in a decayed section of town, with roofs you could scramble across, trecherous areas that urchins could pass through but other people had trouble...meh, not an unusual combat, but the alley situation became fun, and the thief was on the roof a lot.
Saturday's game had some fun terrain and an encounter I'm still pleased with (it must have been really irritating from the player perspective). The first one was a boat landing near a swamp, with a ruined building and an old road--so a good mix of solid terrain, difficult terrain, and blocks to hide behind. I was a little worried I'd wipe the floor with the party (four gnolls, three hyenas, vs. a group of first-level adventurers), but it worked out to be a pretty balanced encounter, and I didn't pull any real punches.
Second encounter--hee--a hedge maze behind a church, with an open Feywild gate drawing antagonists through. Partly there was a mix of of monsters--a brute, a couple of ghosts, and a few modified imps (causing blindness instead of poison). The parts I had fun with--the party had to lug large (150-pound) rune-covered stones from around the maze to shut the gate down, and it had a countdown timer measuring the rounds until it summoned a new Unpleasant Thing. Much fun :)
Need to work out some sort of fast-and-loose cinematic athletics system for swashbuckling leaps and chandelier swings.