I'd suggest State of The Art 2073 then.

War! sucked because of a number of issues, not the least of which were a lot of writers leaving, problems with editing paid-for work with new writers, drifting chapters, and the fact that it would be better named "Bogota!" than "War!". Also, major, MAJOR power increase in the equipment section, especially for CommLinks, despite the high expense and availability of the equipment. I'd get the PDF if you want to be a completest.
Attitude is a decent book, not as good as the old Neo-A stuff, but a step in the right direction. It's almost all fluff, with a small amount of gear (In bad tables and even worse fluff. Editing errors, I believe), and no power increase. All things on how the world really is. Compared to old Shadowrun, not really as good, but it's a sign that CGL is getting it's drek back in order.
If you're getting a group in order, RUNNER'S TOOLKIT! IT'S A MUST HAVE! The sheer amount of awesome they put into this box set cannot be told! Honestly, I brought it with me to a new Con started in the area, and everyone just marveled at it and what it had, and how useful it'd be for beginners and experienced GMs and Players. I didn't see anyone have the same kind of fit over any other game item ever.
Street Legends is a fluff book that details a lot of big names in Shadowrun. It's just characters, and high-powered ones at that. STATS FOR LOFWYR for $Deity's sake! It's getting mixed reviews mostly due to people going, "They're Mary Sues!" and "They're exactly what we need to fill out the world!".
Street Legends Supplemental is a PDF-Only boost to Street Legends, and is good if you want a taste of Street Legends without the expensive outlay.
Despite the joke at the beginning, State of The Art 2073 e-book is a good buy for the vehicles on their own in my mind (Even if the art is... Meh). It moves the Metaplot along, and has a lot of other things that extend previous books and the world itself.
The Way Of The Adept gives Adepts some much-needed loving, and if you like them, you'll love this e-book. It's pretty cheap, too.
I'd pass on the other e-books not mentioned above (With the exception of Missions), and get Runner's Black Book (Which is ONLY in book format! Don't go looking for the PDF, it doesn't exist), which combines them, with improved art for This Old Drone, and adds a few new items. I've got both sets (PDF and Book), and do indeed find the book worth the purchase just because it's so much easier to carry around than printed out sheets in a binder.
*Catches Breath* Hope that helps.