Brands I think are essential to my collection and of which I've either had, have or will have examples:
Stanwell pipes are widely touted as the best "factory pipes", a title for which they would probably battle with Savinelli or Peterson, depending on who you're asking. If you ask me, the Danes win hands down
. They did some pretty revolutionary things in pipe-making and produced some very cool shapes, from traditional to wild freehands. The way they worked in collaboration with the great Danish pipemakers is pretty cool. The Made in Denmark pipes that I've had have all been great smokers. I have only one right now, a bent bamboo. It doesn't have "Made in" stamping, so I can't tell if it's Italy or Denmark, but it smokes amazingly well and the fit and finish are top notch. I'm on a bit of a Stanwell PAD episode right now.
Dunhill, of course, for their history, their innovation and their marketing genius in making pipe-smoking something to admire. A perfect combination of marketing, innovation and quality is what took them to the pinnacle of pipedom. The ability to date them to the exact year of manufacture/selling is also a very nice feature. And they're pretty darn nice pipes, as well. Their classic shapes have defined what a pipe looks like.
Meerschaum pipes are something every pipesmoker should experience. And while the vintage/estate meers can be good smokers with great history behind them, the new innovations by the meerschaum carvers with their "briar style" delrin tenons, teflon shank inserts and open draws make modern meers something really great. So something from Altinok, Baki, Meer Queen or one of the other modern meer companies is on my list.
Missouri Meerschaum Cobs are another pipe of which every pipe-smoker should partake. No nonsense and they deliver a good smoke for a few bucks. Not my favourite smokers, but they do really well.
Brigham pipes for the Canadian pipe-smoker. There is a great history with this company, right out of Toronto on King Street. They have more than 100 years of history behind them and, while they've now moved production to Italy and France, they still make nice pipes that smoke well. That said, the real gems are the older Made in Canada models, both for nostalgia and for great smokers.
Mark Tinsky is an icon in the American artisan scene. He's been making very good pipes for a very long time and he continues to turn out really great smokers--and great lookers--at a consistent rate. He's a heck of a nice guy to deal with and I think he cuts an apple shape better than most out there. Also, his Coral finish is a ridiculously good deal for a great-smoking pipe.
Peterson is a brand with which I've had poor luck. I just think I'm not a Peterson guy, or I haven't found the Pete that is for me just yet. But something keeps me coming back to at least ogle them regularly. Their distinct shaping, the history and a certain affinity I feel for all things Irish keep pulling me back in. Maybe one of their Sherlock Holmes meerschaums will do the trick :D
Savinelli is another brand that hasn't agreed with me, but mostly because I find filters and systems a bit finicky. The longevity of the brand, the quality of the examples I've had and the smoking qualities all make Savinellis winners, despite my personal preference for other brands.
Castello is a brand that holds a lot of fascination for me. I like their finishes and their shaping, but far too often their pipes are too large for my tastes. I've finally found one that is the right shape, size and finish, so it's en route. Their reputation as great smokers out of the box and for years thereafter is well established. They are probably the champ at the high-end range of the Italian makers in terms of quality, volume and history. The history and the philosophy of Castello is also very interesting.
Other brands that I think are fascinating and would make great additions to a collection are Barling, Comoy's, Charatan and Sasieni (all fro m the appropriate eras, of course).
If we get into artisans, we could be here all day