jazzhound, microphones are a personal choice, a personal tool and each engineer uses them in their own way. any studio worth anything has the usual compliment of neumanns, sennheisers, beyers, shures, akg, rca etc. the better the studio, the better the mike locker. one should never have to ask: do you have a u-87, a km-84, a u-47 (tube or fet), a u-49, a dx-77, a 44 (in fact, they should have at least 2 of everything-one of something never helped anyone), etc.
i have an extensive mike collection of my own and it's all the kind of equipment that a studio would never pop for: Brauner VM-1`s, DPA 4006's, 4007's, Sanken CU-41's and CMS-2's, Coles 4038 ribbons, Neumann USM-69 etc.
i got tired of going to a studio and finding out that the high profile client (eric or pat, for example the kind of client that you only have to use one name) in the next studio had booked all of the good stuff (or found out that they might advertise that they had a certain esoteric microphone only to find out that it hadn't been working in years)
as far as changing techniques from analogue to digital, i never thought that way, to me a recording that would work in dig would work in analogue-i would have tried to match the project to the format
i still like 2" 16track no noise-now there's a fat sound (or is that phat?)
so, core microphones, and some of these are going to seem obvious: SM-57, SM-58, U-87, MD-421, MD-441, RE-20, U-47, Fet-47. DX-77, 414, C-12, C-24, KM-84, (i can never remember the numbers of the new neumann line: 149's, 184's etc) and 3 M-50's if a studio can find them!!