Just for fun I checked the Vegas download size for the versions I have in my hard disk. And the results are (as shown by Vista):
Vegas 4.0e: 42.7 MB (this is from D/L page, not directly comparable to other numbers)
Vegas 5.0: 42.2 MB
Vegas 5.0b: 42.4 MB
Vegas 5.0d: 42.9 MB
Vegas 6: N/A
Vegas 7.0a: 117.4 MB (with MediaManager)
Vegas 7.0b: 138.2 MB
Vegas 7.0b: 137.4 MB
Vegas 7.0b: 137.5 MB
Vegas 7.0b: 144.1 MB
Vegas 8.0: 74.3 MB
Vegas 8.0a: 116.3 MB (!)
Vegas 8.0b: 117.0 MB (!)
Did they include MM from 8.0a onwards or how can you explain the difference? VP8b d/l is now as big as was 7.0a with MM.
Anyway, Vegas is not anymore the compact, tiny NLE as it used to be. But then again, whio can remember the time when we used to call web browsers as "light and compact".