I was a judge for the Luxury Chocolate Salon & talked with Alice Medrich about this...
You want to take care to avoid blowing your palate out. Going Dark to Light is best because: 1. An unadulterated palate can take in the subtlety & flavor profiles in the dark chocolate. 2. The fat in light chocolate coats your tongue and again, makes it difficult to taste nuances when you go darker.
As Alice said, whether you go light to dark or dark to light, whatever you taste last will be exacerbated (either really sweet or really bitter).
It's best if you try multiple chocolates within the same percentages first. So try 5 different 70% cacao's and you can mix it up not only with different vendors but also, single-origin chocolates are very intriguing. If you can get your hands on it, try Claudio Corallo Chocolates (they have a very interesting approach, I can get some tasting notes for you), Askinosie has some intriguing chocolates as well. I'd also seek out Amano Artisan Chocolate bars. They won several awards at the Luxury Chocolate Salon 2 years in a row.
(I went to a guided tasting once and after trying several of the good chocolates, they threw in a Hershey for comparison. It was incredible how vastly different it tasted next to the others. Also, I can imagine it would be even more drastic now that they've taken most of the milk out of Hersheys and added in other fillers.)
My friend Eagranie from the Well-Tempered Chocolatier has Product Reviews on her site:
http://thewelltemperedchocolatier.com/category/product-reviews/
(Eagranie is a trained chemist and provides an intriguing insight).
Also, if you're looking for flavored bars, do try Eclipse Chocolate's Lavender Sea Salt. I had a rough time sharing this one with people!
In general, I'm not a big fan of Theo Chocolates but I understand their products are gaining nationwide traction. Their Bread & Chocolate bar is a favorite (not of mine but others I know really like it) and I really like their Jane Goodall bars -- both the dark and milk chocolate.
For confections, some of my favorite come from Posh Chocolates out of Montana and Fiori Chocolates from here in Seattle. Fran's sea salt caramels are out of this world.
It's been a while since I've had Vosages chocolates so I don't think I could comment on them other than to say the Bacon bar is gross. Avoid it at all cost.
** Recommend wine crackers to cleanse your palate.
** Also, Alice recommends warm water to cleanse the cocoa fat off your palate.
http://seattletallpoppy.blogspot.com/2009/01/interview-with-first-lady-of-chocolate.html