Visit "Daves Garden Watchdog" for feedback on reliable dahlia sources. I order in late winter. But I also make more than a few Wish Lists, during the Winter.
The Best of anything is subjective, there will be many opinions.

Best 3 for what?- Showing? Lots of blooms? Cut flowers? If we knew what you had in mind as "Best" we could help more. For instance- if you're looking for show blooms in the AA size- the biggest winners last year were Zorro with 222 awards; Inland Dynasty with 212 awards & Ivory Palaces with 70 awards. If this is the kind of info you're after I can look up the other winners in the other classes for you.
If you go to the Colorado Dahlia Society site of Suppliers you will find a whole list of suppliers that are reliable & a whole winter's worth of browsing through their websites- a lot have pictures- some are better than others- if the picture of the bloom on one site looks bad, chances are you can find it on another site & the picture & the stock will be better. I usually figure if the bloom looks bad in a picture, maybe the grower hasn't got such good stock & go elsewhere. I figure if someone's trying to sell something they should present it well.
The Big List on the Col. Dahlia site also will tell you who sells what variety if you see it on one site & it's sold out, try another.

Here is a link that might be useful: Colorado Dahlia Society Suppliers list

I need the following.
3 best AA
3 best A
3 best B
3 best BB
For a first time grower and maybe exibitor.

Stan C

Stan your request is too broad. You'll just have to make your own choices based on the types and colors you mentioned.

Along Plantlady's line of advice- here is another link to the Colorado Dahlia Society's website. This one shows you the top winners from 2004 of all sizes and colors and shapes.
As you go though the list watch for C- cactus, SC- semicactus and LC laciniated. There are plenty of photos to help you whittle down your list.

Look for R or DR for red/dark red, DP for dark pink, BI for bi-colors. For example, BIy/r would be bicolor yellow and red.

Here is a link that might be useful: Top 50