I thought I would detail my problem and how the tiered system works.
1. Paperbacks
I barely ever buy paperbacks, but I do receive a bunch as gifts. I'm not a large fan of paperbacks, but I do have a thing for the ones that have special pages that are unevenly cut. I don't know what they call this technique but it gets me every time. A good example is the Centennial Edition of "The Grapes of Wrath". What do they call this technique? Anyway, I tend to take paperbacks on trips because I'm not really concerned if they get damaged and they are light weight (which is great for backpacking). I may leave them at hostels too if I need the space, but I have yet to do so.
2. Hardcovers
I try to buy most of my books in hardcover, because I just like the structure. I don't like when the spine on paperbacks gets creased, and while these spines crack, I never buy a hardcover with this problem and I don't crack them myself. The preference is for the larger first edition copies, but I find I have a lot of undersized firsts which really aren't worth anything... but I like the originality of the artwork. Note that a first edition will eclipse the third tier.
3. Modern Library / Everyman's Library
I love these types of editions, both smaller sized hardcovers which have a consistent spine which looks GREAT on my bookshelves. I prefer Everyman to the Modern Library's silver covers, and Everyman also has chronological histories of the works of the author, his life, historic events going on in society at the time, and works that other authors are publishing at the time. It's great reference, and it's really helpful for book club discussions.
4. The Folio Society
Each work is of a limited print run, and they are all works of art. I also LOVE slipcases and I can't tell you why. Again with the structure, I imagine... and they just make more sense then dust jackets which tear easily and really don't protect the book from anything, especially dust.
5. Easton Press & Franklin Library
These works are bound in leather. Easton's are all full leather (mainly bonded) and Franklins can be faux leather, quarter leather (where the spine is bound in leather) or full leather. These books look great on the shelves, but they are harder to read. I usually wear white gloves so my hands don't transfer their natural oils, but this is fairly OCD of me. Other than the look, I really enjoy the high quality paper and smell of the leather. It's hard to pick a favourite of the two, but I think I enjoy the Franklin Library older versions (from the late 70's) the best because the quality of the leather is remarkable.