Lower thirds (background for your text, placed at the 20% lower part of the event) can be made in many many ways. They can be animated or just stills. You can use any type of transition to make them appear and disappear. You can generate pre-made animated lower thirds in Production Assistant, in Boris Graffitti, Heroglyph etc. But it is really fun to create them your self, completely adjusted to your film. You can use photoshop to generate the background pictures (that contain e.g. motifs from your film). You can generate animation with the track motion tool.
A very simpel way to create abstract lower thirds can be done completely in Vegas. Just create a shape with the track motion tool or the coockie cutter tool. Place a copy of the event you are playing in the video also in the track with the track motion (or coockie cutter) and apply a blur (or any other effect you like). Play with light and opacity etc. Using your imagination will result in very cool custom-made lower thirds. Much nicer then all the pre-made stuff.
And the ‘Upper Thirds’ (nice word!!) can be made also with the track motion tool. To avoid losing to much of the scene, you can make them e.g. 50 transparant.
Theo