I've had this for years and is one of my favorite investments despite the multiple price bumps, some under the radar things that haven't been mentioned
Iredeemable Ant-Man by Kirkland- The premise of this book is just a super hero is a complete and utter dick, great fun at the start but i think it kind of limps to the finish line, still worth checking out for a fun read. Great if you're looking for something a little off the wall.
Madrox Mini-series and X-Factor Volume 3 by David- Peter David takes some street-level mutants and forms a detective agency out of them, in the process turning Multiple Man into one of the best Marvel characters around. This series is also a great slow burn, plot threads will hang around in the background for years before being fully resolved, and by the end a complete, whole story is told from front to back, which is difficult to do in comics these days. Also features one of the most heartbreaking moments I've ever read in a Marvel comic. heavily recommended for fans of street-level detective stuff.
Fantastic Four by Waid- I think this is the "editor's choice" right now and for good reason, Waid took the characters in an interesting and dark direction and the "Unthinkable" arc is a great story that really preys on the weaknesses of the Fantastic Four, plus it features Doom being great, which you really can't go wrong with. If you want to read a good Fantastic Four series but have no idea where to start, this is the arc right here.
Ghost Rider by Aaron- this is what Ghost Rider should be, just plain over the top vengeaful fun, Aaron really understands that a flaming skull riding a motorcycle doesn't need to have a ton of dialogue or even make much sense. Recommended for B-horror movie fans.
X-Statix by Milligan- superheroes acting like reality stars while dropping like flies in a super fun x-series, very out there for Marvel but pretty damn cool. Great little satirical story, good for humor.
My personal favorite pick goes to the Exiles series. Essentially boils down to a bunch of nobodies going to alternate realities to "fix them," so essentially a big long series of "what if's" with recurring characters that can die at any moment, good stuff for the first 20-30 issues before falling pretty heavily off course, but the start is great! If you're a little more versed in Marvel lore, there are a ton of in-jokes in this and it revisits a lot of cool classic moments with interesting twists.