Unless you are hoping for a Ness Vision or a color not offered with the '08's, you will not get a better deal on a Vision than right now. 

All of the issues discussed here can be fixed on the '08's, especially if you have a good dealer.  Dealers have the latest software updates for the EFI and a lot of the problems noted here are not universal.  Speaker/radio issues - I've seen both ends of the spectrum discussed here.  Stalling issues  - almost non-existent with  the latest batches of '08's.  Heat - If you are under six feet tall, get the deflectors.  If you have long legs, it is manageable.  The '09's will be just as hot. 

Advantages for buying now:  You can probably save close to $4,000 under sticker.  Better interest rate than the '09's will have.  You can still find any color.  

If you wait:  Much less likely to get a deal, especially if there are '08's on the floor.  Slightly higher interest rate.  Pre-order may or may not arrive when they promise.  You will have lost months of riding one of the nicest bikes on the planet.

I think the "issues" discussed on the '08's get blown out of proportion sometimes (unless they are happening to you) and for the vast majority of us it has far exceeded our expectations.  The '09's will not be perfect. 

I'm glad I didn't wait, warts and all.  $4,000 off would have sure been sweet.

Even if the deal would have sweeter today, or with an '09, I'm glad I was the 2nd one to roll out with a Vision in my area back in November. It has been one great 8 months with an average of 2,150 miles per month. Thank you Victory!

The decision, of course, is yours.