use h.264 compression. i dont use vegas, but my guess is that you'd probably have a setting for .avi, .wmv, or .mov. I would save it as an .avi, if its a bigger size and your trying to compress it a bit more. If you have a choice for broadband high/medium/low, those can affect your video as far as size and what not as well. With final cut i set my videos to h.264, broadband high, 640x360(depending if they're widescreen videos), a step down from best, and .mov, and i've been able to get a 11 min HD VID around 100 megs.
Facing your biggest fears, and being honest with yourself, and everyone around you makes you stronger and more respected. Stay true, dont hate, show love, and change the world.