Lots of great cabs out there these days, and luckily they seem to sell for cheap on the used market. Cabs can be more fun than amps, some days!
I've had a Mesa OS straight/slant for the last 10 years and it's typically my go to. Every amp I own sounds good through it. Some amps excel through other cabs, but I just don't seem to have a problem matching any setup through that cab and making it sound great. I also refute all claims of these cabs being boomy or muddy. They're honestly quite stiff when compared with a lot of other cabs due to the air tight construction.
I've also owned probably 15-20 of the Peavey Butcher/412ms cabs. I have a full stack of them right now that I paid less than $120 for, all in. They're also great sounding cabs with the K85's in them. They are so solidly built that they also can be a bit stiff when compared to a 1960 or other similar styled cabs, but as a metal guy, I love the quick response.
I picked up a Friedman cab from a fellow forum member last year, and that has pretty much taken over as my go to cab for all marshall style amps. It just compliments so well, seems to widen out the sound spectrum without taking away from the upper mids, and just makes each amp sound huge and musical. Really in love with this thing.
Honorable mention: Marshall Mode Four MF400 cabs. These babies are well built responses to the Mesa OS craze from the late 90's early 2000's. They do not have the airtight construction, so they can be boomy, but I make sure to open them up and tighten down all of Marshall's notoriously loose hardware every now and then and they stay good and tight under riffing. Really love these with my Splawns, and they also do well with 5150's when tuning down a bit.