If you have rythm, play the project and hit the M key on the downbeat. Or upbeat, or any funky drummer kinda fill ya wana pull off. Set "snap to markers" in the options menu. While editing, jump to markers via ctrl/arrow or click on the red flags.
If your doing multicam editing, do a search here for (multicam?) info on the track motion/markers/global split events-tracks setup that makes good use of Vegas.
If your tune has a constant beat, you can set the BPM in File > Properties > Ruler > Beats per minute. Then, right-click on the ruler and select "Measures and beats" and the grid lines will line up with the beats. Options > Metronome can help line up the tune with the grid. I do this with tunes I've built in ACID, since I already know the BPM. Or, if you're not sure of the BPM of your tune, ACID3's "Beat Mapper" can calculate it from a .WAV or .MP3 file.
///d@
You like the music you're working on/with? Go with the "m"... markers... beat it your own way, with the spots you want to "push on". Tailored your way... You can easily "slice" it when you get more into the project. Easy to use; to mark OR delete the mark (important it'd be THAT way too; easy going...)