First of all, my power to weight ratio sucks. Okay, well, it's decent in bursts. My 5, 10 and 20 second max power - my sprint power - is pretty high, and even though I'm a fat bugger, my power to weight for those durations isn't bad. Chalk it up to years of doing squats, and doing hard, powerful leg movements playing rugby.
Second, my five minute and twenty minute power, as measured by power to weight ratio, aren't bad. They aren't great, but I do have enough power at those intervals to be able to bridge up to a break over the course of four or five minutes, to do a two-lap move in a crit, or to stick in a long break on a flat course. So good so far.
Third, I have an enormous hole in my one minute power. It's just not that. Sadly, the one move I've done consistently in crits, is a kilo move. I've gone with guys who go a thousand meters (or about 1:15, more or less) out from the finish. That's *the one* kind of move I should not be doing. Consequently, I blow up after about 600 yards, and typically last year would get passed by twenty guys, then would pass ten or 15 on the way back in. The really good finishes I had last year, where I was setting the tempo, occurred when I started a move a couple laps out in a crit (five minute power, anybody?) or when I sat in, and didn't spring it until four hundred or five hundred yards from the end. This was *close* to what I should have been doing in races.
Fourth, do you really want to know what I should be doing? Take a look at the picture below. It shows mean maximum power on the Y axis, and time on the X axis. It's my chart from this morning's workout, which interspersed 12 seated "form sprint" accelerations from a stop, or stomps, in the middle of a 30 mile zone 1 / 2 ride.

That picture isn't too clear, but you can click on it for a bigger version.
Do you see where I drew the intersecting lines? I was going for 12-15 second efforts, not trying to keep the power up for a long period of time, just trying to accelerate sharply for 12-15. You will notice that the power starts at around 1320 watts, and hangs up over 1200, decreasing gradually, for 12-15 seconds. I could probably pull another four or 5 seconds of >1200 power out of this if I really had to. What's more, is these weren't super-peak efforts, they were hard but I was concentrating on maintaining perfect form, and I wasn't doing a standing jump, which is a bit more powerful. It is also the average power for 12 of these accelerations. My actual peak power on most of these was in the 1325 - 1350 range, with 5-10 seconds in the ~1275-1300 watt range. When I'm fresh (like after a rest week, and not in the depths of overload) and working really hard, I can pull closer to 1450 - 1500 watts for 15-18 seconds. I know this because the Cycling Peaks software shows me the power curve I rocked 3 weeks ago when I did a similar workout but had much fresher legs.
Know what that all means?
It means I'm a classic sprinter, and my most-likely-to-be-winning move is from 250 yards or so, maybe a bit longer depending on the course and the competition.
What the PowerTap has effectively indicated is that if I want to win, if I can't get into a good break a long ways out (and make use of that nice, juicy 20 minute power) then my next best bet is to sit in, pick a good wheel that goes kind of early, maybe at 600 or so, and ride that sumbitch up to within 300 yards of the finish, then jump for all I'm worth, sprint so hard my eyes bleed, I should be able to drop some people. There aren't too many Cat IVs throwing that kind of power, so I need to conserve, and then uncork it when it will do the most good. Screw the kilo moves. Not my bag, bay-bee, as the great man said. (Of course maybe this will make me a good leadout too... you never know).
Right now I'm at the tail end of Base 2 - my basebuilding. I'll have a rest week soon, then start a build period perhaps 10 days from now, during which I will begin racing in earnest for the season. I can't wait.
They say that success starts with knowing one's self. The PowerTap's harsh, unyielding eye will give you self knowledge if you admit your own ignorance and show a willingness to learn. Figuring out what your gifts are, and what your deficits are, is a pretty fair first step on that road to self knowledge, I think.
So yeah, that's one of the things the PowerTap can do for you.