James Spencer of Basic Brewing Radio did an experiment a while ago, where they brewed beers with and without the trub in the fermenters. The beer with the trub apparently had a better flavor and aroma, but I think the difference was slight. A small amount of trub is beneficial, as it adds some nutrients for the yeast. (At least, that's my understanding) If you can leave some or most behind in the kettle, don't worry about some making it in to the fermenter.
+1 to the yeast washing, I find it much easier to do without trub.
I don't have a spigot or valve on my kettle, so I use a siphon to transfer from kettle to carboy. I keep the bottom of the siphon just below the surface of the wort, to help avoid picking up too much trub. Once it gets low, about a gallon remaining, I drop it all the way in to get a little of the trub purposely. Most stays behind, but I like to have some in the carboy.