Just wanted to offer up a free little program I ran across that's really helped me cut into the HD rendering times for Premiere Pro (particularly if you have a slower computer and want to work on 1080p). It's called "Cheat Engine" and basically helps to focus your computer's resources to one exclusive running program (in your case, Premiere) to help speed up the process. It's help me cut hours off my rendering. Helps a ton.

Here you go: http://cheatengine.org/downloads.php

Edit: Some of you asked for a tutorial:

MAKE SURE YOUR EDITING/RENDERING PROGRAM IS ALREADY RUNNING

1. Start program
2. Select the left most button (computer with magnifying glass icon)
3. From the list, select your running editing/rendering program
4. From the right-most menu, select "Enable Speedhack"
5. When the Speed option appears, replace the current value with 0.1
6. Select Apply
7. Leave CheatEngine running and begin your render

That should do it

I can't say based on experience, but I have to assume it works the same way because when you start the program, it asks you to choose which (running) program you want to focus on. So if you have Vegas Pro running, you should see it in the list as well.

Yep, I set the priority too and I try not to run any processes I don't need. In combination with the program, it normally does it pretty fast

Here's a short guide on how I set it:

MAKE SURE YOUR EDITING/RENDERING PROGRAM IS ALREADY RUNNING

1. Start program
2. Select the left most button (computer with magnifying glass icon)
3. From the list, select your running editing/rendering program
4. From the right-most menu, select "Enable Speedhack"
5. When the Speed option appears, replace the current value with 0.1
6. Select Apply
7. Leave CheatEngine running and begin your render

That should do it

Hope you guys find it useful If you notice no change in the time, I've heard some people fare better in changing the value to a higher number instead of 0.1, though 0.1 has apparently been working best)