It is a really weird place that the US has backed itself into. The Taiwan Relations Act, passed by Congress and signed by President Carter, compels us to keep selling weapons. One of the Three Communiques says that we'll slowly wind down our weapon sales to Taiwan.
Agreeing to not do something that your own laws say you have to do isn't very smart, Mr. Reagan.
The most important part of the current weapon sales discussion is that the US is continuing with plans to get Taiwan some kind of diesel submarine. Since no one else in the world is willing to sell to Taiwan (for fear of losing Chinese trade), and the US no longer makes them, the US is apparently going to sell them the plans for a diesel sub.
Ten or five years ago, that probably would have made a lot of sense. But China is now rapidly increasing its number of nuclear subs. I'm not sure inferior subs will fix the balance of power.
In reality, though China will get huffy about this (as they do all of the weapon sales), I'm not sure how much it matters. But, overall, I'm glad to see this policy continue. I think that maintaining a decent deterrent in Taiwan is a good idea, as long as it's never a sure thing (leading to a unilateral call for independence.) A "balance of threat" approach is probably for the best, for now.