You've probably discovered all this, but just in case...
For a long time, I used the 'Last 100 Active' tab, but then switched to the 'Active' tab, and that is pretty much all I use now. As long as you are logged in, it will show the topics with activity since your last visit.
The arrow behind the poster's name in the 'Last Post' column will take you to the most-recent post in that topic. I'm not aware of a way to take you right to the first unread post in a topic, but as long as you keep checking in regularly, you never have to scroll up too far to find the new stuff.
