dave,
Update: So I bought the Luigi Viprati....and it's the best smoking experience I've had so far! It trumps my cobs and savinelli 320

In my humble opinion, if you're going to buy a briar, go for a really good one with premium quality briar, otherwise, just stick with cobs. I think the briar of my sav 320 is low quality as it's at the lower end of the savinelli range? I prefer my cobs to the 320 but the Viprati trumps all! Brilliant smoke
I once owned around 6 Viprati's at one time and everyone smoked really nicely. They were all a 4Q so the grain was fantastic. I am glad to hear you love how it smokes, Viprati's are a good example of how well Italian pipes smoke. Having a shank dimension of 4.0-4.5mm makes for a nice dry smoke. Seeing as you love your Viprati, you can now expand into the world of Italian factory pipes such as Castello's, old Caminetto's, Radice's Ser Jacobo,Ardor to name a few.
Here are a couple of examples of really great pipes for a modest some of money.
This pipe is nothing to look at but it will be a great smoker. These older Caminetto's were carved by Radice and Ascorti and smoke as good as any Italian pipe made. They are from the 70's in most cases. I have owned around 5-7 of these over the years and the only reason I no longer have them is the stems are made of acrylic which I don't care for anymore.
http://briarblues.com/jio53.htm
Here is a Castello for 165.00 that should be an awesome smoker.
http://mkelaw-pipes.com/html/pipee3731.html
There are so many more examples of great estate pipes for a great price. If you want to get into the world of artisan pipes I would recommend Ryan Alden for a new one. I own 2 of his pipes bought brand new and both are superb smokers. He goes by the handle of Lonestar here. Another member who carves a great pipe for the money is Zack Hamric, he is a moderator here and his handle is Zack. Another option for you are pipes made by a British company named Willmer. They make an awesome pipe an I just bought 13 of them at one shot from an ebay seller. That is how much I like these pipes.
If you want any help picking out pipes, just pm me and I will be more than happy to help you.