There are so many I like. I don't know if I can pinpoint a favorite. Always loved the Carol Danvers Ms Marvel figure from the 3pk with Radioactive Man and Ultimate Cap. I liked Bor a lot, and that one-off look for Unworthy Odinson. Still really wish they reissued X-Force Archangel, as I loved that color scheme for him. I too love that A-Force She-Hulk, even with the dated hip articulation, but she's not my favorite from the set. Elsa Bloodstone is. I think if I start including 2pks, it gets more difficult to narrow down. But I think my overall favorite choice goes to the Colossus that came with Juggernaut in that anniversary set.

Colossus and Elsa Bloodstone are great!

Yeah... I guess my favorites from this context would be the one's I don't own yet and would buy separately -  specifically Blastaar and Hela

For me it was Colleen Wing and Jewel Jessica Jones. I can't think of any others that I've ever bought loose like that. 

I tend to go the other way. Buy the boxset and sell of the characters I don't want

I only have one, but I do really like it, and that's the Ultimate Spider-Man from the 2-pack with Vulture. I got him from an eBay seller back when I first started my Marvel Legends collection. Only has the two alternate hands for accessories, but he's got the blue pins in his arms instead of the red ones the version from the Space Venom wave had. I remember hoping that they would eventually repaint him into the symbiote suit someday, and kind of ironically they finally did last year... in a 5-pack containing four figures I have absolutely no interest in, lol...

A-Force Sif. 

Another one I love is Storm from the set with Thunderbird. Not only an early example of pinless joints, but a fully unique sculpt. I remember the senses of relief, disbelief, that we finally got a figure of this version of one of the most important X-Men, from one of their most important team incarnations. 

Back in the day I bought just the Spider-Man from the old ToyBiz Sinister Six box set. I loved the look of that figure, but some of his joints were super loose. I bought the Black Cat from that set at some point as well. What a terrible figure.

I also bought the Spider-Man from the ToyBiz Fearsome Foes box set. But I eventually bought the entire box set unopened on eBay because I decided I wanted all the other figures in the set. And it was actually cheaper to get them all together than individually.

Vertigo is mine. I bought one loose and planned to wait for a sale to get another, but that didn't happen. 🙂 I'm working on improvements, but was so excited to finally get this character.

Bought Agony loose, but then also bought the boxset because I decided I needed a normal-sized Venom.

Aunt May!

Colleen Wing is great - ended up buying most of that set separately after the fact, and surprised her unique body has never seen a re-release.

Red outfit SDCC Giant-Man is one, oh, and Astral Doc Strange.

Callisto was one I was going to get separately but then I bought the whole thing and sold off Cyber and Omega Red. Wolvie won me over.

It makes more financial sense to buy the set and then sell off the ones you don't want then to pay individual shipping on each, especially if original shipping is free.

Elsa Bloodstone bc she's hot and has guns.

I tend to just buy the whole set instead of hoping to get a decent price on the one or two figures I want.  Hela, Sif, and Radio Active Man are a few that I've enjoyed.  

Like others have said, I'm more likely to buy the whole box and sell or trade the ones I don't want. However, I managed to get a loose Rhino (from Fearsome Foes set) for like 20 bux Canadian at a local con years ago. That's probably my favourite ever figure from a box set.

Couldn't find the X-Men 275 thread. During the windowless packaging era, I've been opening the boxes promptly to check if any funny business or bad paint apps. I either put the figure back in the box or put them in a bag with other figures or boxes.

I recently took out the X-Men 275 Psylocke and noticed there are two symmetrical specks of paint or paint scraped off on the chest. I assumed the upper torso was molded in yellow, so am guessing paint from another figure or cardback or box transferred to the chest. Anyone else have this? Not sure if I should try to rub the specks off or try using sticky tape to transfer it off.

I tend to buy the whole box as well, but when I first started collecting there were a few SDCC exclusives I desperately wanted, and Moonstone will go down in history as the paid-too-much, never-left-the-display figure I bought out of the set. Never did get around to finding Hela at a reasonable price, always wanted her too.