For almost all those who have posted in this thread about grinding, what needs replacing is the blocker rings that sit inside the syncro hub. This does not require a whole new tranny, just fitting of new blocker rings. Obviously labor will not be much (if any) cheaper, but you can probably save some money by ordering just the rings and not a whole new tranny. The rings are definitely easier to replace than a gear, so if you're getting a pretty consistent grinding I'd suggest that you get the blocker rings replaced ASAP or you will be SOL soon enough.
For those of you worried about grinding problems, a simple habit to get into is to start the car and leave it in neutral for around a minute. This allows the input shaft of the transmission to spin in the housing and splash oil over the entire gear assembly (hence a "splash" type system), lubricating all of the moving parts including the blocker rings. This simple step will increase the life of your tranny and best of all costs absolutely nothing!
I learned all of this info at Terry Haines' tranny seminar and I really feel obligated to promote it over and over again. Even if you never plan on replacing your tranny yourself you will learn invaluable info that will allow you to diagnose problems and avoid BS'ing dealers and mechanics that will try and take you for a ride. Best part is, if you do want to work on your tranny yourself you'll be more than able after this seminar...you really don't know what you're missing til you take it!!!