Considering that there most of the tab sites are hosting Guitar Pro files, it should tell the guitarist in you to keep up with the times. Guitar Pro 5 is an excellent tabulature writer, reader, and player for tabulature and sheet guitarists.
From what I've tried, I've opened numerous Guitar Pro tabs and each music track was excellently split and neatly organized with both sheet and tab notation. I was pleased that there is a practice mode where the tempo is set low and steadily increases as the song is repeated. I am also impressed with importing songs to tabulature. Every now and then I hear a good midi song and want to play along with it with my guitar. Guitar Pro allows you to import midi and does its best to transcribe it to easy to read tabulature. Of course its not going to do a perfect job of directing your fingers but it does find the correct notes which is a great transcribing time saver.
I notice that there are many and much more features in Guitar Pro but from what I've tried, it seems like an already excellent product.