The key is to put them in boxes. Anyone can use sleeves and binders, but boxes are also necessary to keep that evil dust away. 120 is much easier to sleeve than 35mm, and you don't need as many sheets as you would shooting 4x5.
I sleeve, and if it is E-6, I take to work and photocopy it.
(you have to fiddle the lightness control, and leave the copier lid open) to make a very poor quality, but fast and cheap, but identifyable 'contact sheet'.
I then write note on this 'contact sheet' and stick it into the filing binder in front of the neg filer sheet just as though it was a contact sheet from a c-41 or b&w neg lier page.
I use Printfile pages, the ones that hold 3 strips of 4 negs each. I like to keep the number of "end" negs to a minimum - better for neg holder positioning. I keep them in very nice binders, but I agree with Garry and may transfer them to boxes. You can get nice clamshell archival ones with binder rings, here is one, but there are others - http://www.bhphotovideo.com/c/product/442251-REG/Archival_Methods_06_102_06_102_Binder_Box_1_5_.html
I use printfile negative sleeves for 35mm to 4x5 negatives. I only use sleeves that accept the plastic hangers so that the sleeves are stored like hanging folders in a metal filing cabinet. All the hanging files are number coded, corresponding to my Lightroom databse. I no longer make contact sheets. All my negatives are scanned and then managed in Lightroom. All printing is done in my darkroom, of course
So the neg sheets are the way to go.
I'll have to make The Space free to install a closed filing cabinet.
This will no problem.
The negotiation with the misses where to put it certainly will...
Those harddiscs come in 1000x less volume,you know darling.;-)
Thanks for all your replies.
rhmimac
To avoid spending much time finding out whether the filing cabinet itself is safe or not (outgassing formaldehyde, and such nasties), only consider the metal ones Pasto mentioned.
But you knew that already.
Are those 3-ring binders for sale at Office Depot that say "No PVC" safe for storing negatives? The Office Depot binders are only about $4 or $5 each.
~Dom