I'm not talking about the supercollectors who have every prop and TP item released under the sun.  I just mean the basics or highly recommended items to enhance the TP experience.

In this group of items I would put-

TP Gold Box, FWWM DVD, Secret Diary, Cooper's Book and Audiotape, Access Guide, Collectible Card Art, WIP, all 3 Soundtracks (maybe Floating into the Night as well?), Full of Secrets book, deleted scenes script from FWWM, and issues of TP Gazette.  Am I missing anything?

Just wanting suggestions for what you consider essential or recommendations for the SERIOUS Peaks fan (also to make sure I have everything in my collection I need!).

The Rolling Stone issue; the Behind the Scenes book; the broadcast episodes with the intros and next time on TP;  old junky vhs with Alan Thicke's Twin Peaks/Cop Rock special; Donohue interviews the cast; Fenn and Otkean at the MTV video awards;  EW's April issue with Lynch on the cover.

t - shirts from the festival, hope that's an o.k. idea.

Necklace made of knotted cherry stems, Andy's "whole damn town" sperms sample cup with sticky copy of Fleshworld,  an anxious personality caused by too much caffeine & pastry... oh & at LEAST one TP insired tattoo (I have 6).

Merchandise is nice, but it won't really transport you to Twin Peaks. Try a damn fine cup of joe (hot!), a heavenly piece of cherry pie, and some "secret" diary scribbling. Maybe followed by a long walk in the woods.

TP Gold Box, FWWM DVD, Secret Diary, Cooper's Book and Audiotape, Access Guide, Collectible Card Art, WIP, all 3 Soundtracks (maybe Floating into the Night as well?), Full of Secrets book, deleted scenes script from FWWM, and issues of TP Gazette. ?
.

Is the Collectible Card Art the Star Pics cards?

TP Gold Box, FWWM DVD, Secret Diary, Cooper's Book and Audiotape, Access Guide, Collectible Card Art, WIP, all 3 Soundtracks (maybe Floating into the Night as well?), Full of Secrets book, deleted scenes script from FWWM, and issues of TP Gazette. ?
.

Is the Collectible Card Art the Star Pics cards?

Yes, not the Post Cards in the Gold Box.  I don't get the craze over those.  They're just pictures.
 

I think your list covers it, coolspringsj.  These are the basics that you can still find new on eBay (T think.)

I wouldn't count rare merch or magazine articles. 

I remember the Donohue show because Eric DaRe's hair looked like Michael Bolton's at the time.