I use Scott/Prinz mounts for all my stamps, even the cheapest, faulty ones. 
I like the black color better than the blue Showgard uses and I like that the stamps are more secure than the Hawid open top style. I use open top for exhibits however and I have no idea why. I also have a high end Scott album set for my US collection and it uses clear open top mounts. I have followed that when I've had to add more varieties to the album (for instance to add spaces for 10A and 11A). I should say I pretty much exclusively use the strips and cut to size using Showgard guillotines.
My main collection is worldwide on homemade pages sized and drilled to match the Scott International binders and I hinge (using cheap 'hinges of steel') the Scott mounts to the pages. This makes things much, much easier when I have to replace a page due to changes in design. I find it relatively easy to replace a stamp when upgrading. (Gotta get rid of those faulty one after all.)
Duplicates are housed in stock books or glassines, then stored on a shelf, in a pile or in a box until I've completely forgotten I have them. It makes it much more exciting when I discover them again in the future...
I've been using corner mounts for covers in exhibits and large Scott/Prinz mounts for covers in the collections. I also use large mounts for souvenir sheets and the like. I did run into an issue with that when mounting the largest items for my Greenland collection (see here for instance) and I solved it with corner mounts and black background paper to simulate the normal moounts. I was lucky several years ago and won a large lot of large Scott mounts at an auction. I very likely have all the large mounts I'll ever need. 
A month or so ago I posted the following on another thread:
I primarily use top loading mounts. They are much easier to use and one does not risk damaging the stamp as is possible with split backs. When I buy new mounts I get the widest size split back strips, at the best price I can find. I then cut them lengthwise following the split in the back. I then have two strips that are open on 3 sides that can be cut down to fit most any size stamp and easily load from the top. Other than recycling mounts I have found it to be the most economical way to obtain mounts. The biggest arguement for not using splitbacks is that you need many many different sizes on hand to suit your needs which can be quite expensive.
One needs a medium sized paper shear and a small stamp shear to properly cut the large splitback mounts down. HINT: When cutting the long strips on the larger shear you need to use a piece of stiff card stock to use as a holdown at the edge of the cutter to get good straght cuts.
In purchasing the splitbacks to cut down, 80 mm wide is a good size to look for. It is about the largest size that come ten to a pack, larger sizes only contain 5 per package. They usually come 240mm long. When cut lengthwise down the split in the back, a pack will yield 20 strip at 40mm high. I would guess 80% of stamps are 40mm or less in height so this size can be cut to fit most stamps. You can get 200 mounts that are 24mm wide from a single pack. At around $6.00 a pack that is 3 cents a piece which is only twice the approximate price of a single Dennison stamp hinge. Shipping of course is most always a consideration so it is best to buy several packs at a time from the same vendor.
I never use the adhesive provided on the mounts, it either sticks to well or not good at all. Glue sticks work the best, for me, providing adequate adhesion but not so much that you cannot remove the mount from the page without damaging the page.
As far as souvenir sheets go, finding full mounts is fairly difficult and can be very time consuming and expensive. As of late I have been using a single clear split back mount, usually size 24X 40 size, to mount my sheets. I cut the mount down the split and then half each of those two pieces. These are place in the four corners extending a couple mm from the edge of the sheet. On larger sheets I may also add these to the middle of the sides. It is not the best way in the world but I probably have thousands of sheets and it easliy gets them on the pages where they belong.
Below is an example, however I used a little larger than a 25X40mm to mount this one. I only use clear mounts in my Scott Platinum hingeless U.S. album, as does Bill, so I've put all the extra ones I have laying around for this purpose.
@22028 wrote:I guess i have a complete different approach as most collectors here.
I use custom sized pages (220-240 grams), fitted into archive quality sleeve I purchase from archiv-box.
The pages are 24.8 x 30.5 mm (w x h)
I'm thinking you mean cm instead of mm, unless the pages are unusually small... 🙂
Interesting posts so far and thanks for sharing.
In Australia I used open top mounts (Lighthouse/Hawid) for the stamps in my exhibit and Transparol (= Herma) corners for covers.
We nearly all (in Canberra) used an ivory goat parchment type exhibit paper.
All other stamps were filed in Hagner sheets.
Some of my exhibit workbook material is in mounts inside the Hagners.
Here I am in the process of experimenting with the US stuff that’s available. My first ream of exhibit paper here matched perfectly (Natural, 68881). However each successive ream is slightly different, and scans as gray, which is not satisfactory.
I bought G & K Herma type corner mounts, which were fine up till 2009 but they now appear to have gone the way of my old Transparol mounts and have warped. The result is an ugly corner when mounted.
I am currently using G&K Imperial 3/4 inch self-stick mounts for everything, but would prefer a corner mount that doesn’t show any edges.
I have also played with matting and quite like the effect.
I recently bought a “whole bunch” of clear Scott/Prinz closed end mounts. I ended up using them to remount my eUSC stamps as they would (particularly iomoon) develop a lean in the open top mounts.
For the more informal displays that I have made this year, I use adhesive photo corners for postcards and text printed onto card.
I use the G&K Imperial 3/4 inch self-stick mounts for covers.
I use hinges or Scott/Prinz mounts for stamps.
I am using photo corners for meters, which is awkward but currently still doable.
Paper color varies (have used ivory for stamps/postcards, white for covers, light gray for meters, and even green and blue for some entertaining one-pagers).
