Hi Matt,
Christmas hasn't started for me yet.
There are a few things you should try to get rid of the inter-trial lag that you are seeing:
1) Download and install the latest Inquisit 2.x update, which is 2.0.61004.7. This update has some optimizations in it that allow you to take advantage of the following suggestion.
2) Add a short posttrialpause to your trial, which gives Inquisit time to wrap up the trial (e.g., deallocate stimuli, compute statistics, record the trial data, etc). For example, let's say your trialduration is 2000 ms and your posttrial pause is 30 ms. Exactly 1970 ms into the trial, Inquisit will stop polling for a response and will use the remaining 30 ms to wrap things up.
Give these two suggestions a try, and let me know if you still see any lags.
-Sean