2 MIDI + (SPDIF or Audio) card recommendations?

Actually, Rain Recording lists that card as being incompatible with Win7-32 as well, although they say it has working Vista drivers. I have no idea how (or if) they test or what constitutes incompatible. One big problem with Win7-64 is that it strictly enforces driver signing i. e. if the driver has not been submitted to Microsoft for testing and approval (and I assume a significant fee is involved here) and provided with a "signature" by Microsoft, it will not install. That is supposed to make it harder to install malware, and to provide a more Mac-like reliability for hardware. I suspect it will also provide further disincentives to manufacturers to support their older hardware, as well as a new revenue stream for Microsoft.

I'm curious - do you need the SPDIF input?  what exactly do you use it for?

if you don't need it then go with a simple m-audio UNO MIDI/USB cable.  it's only about $35 or so.

Do you think it makes more sense to look for a 2x2 MIDI card w/ at least one audio input (for the mic), rather than a 2x2 MIDI+SPDIF?  Or should I buy the MIDI and Audio/SPDIF separately?

Could I just buy a couple of cheap USB MIDI cables?  Will those work just as well as a "real" MIDI interface?

Does MIDI via USB tend to have more noticeable latency than MIDI via PCI?

+1 on the M-Audio 24/96 and UNO usb midi interface. I have both as I needed a similar set up with two midi inputs and outputs.

yes, that's what I would do, get an inexpensive USB MIDI cable (but not too cheap, I'd go with something that's guarenteed to work with win7).

even the older m-audio 24/96 cards should work with win7/64 - it's the drivers you have to worry about, not the hardware.  as long as m-audio has drivers for it then they all should work.  are you asking because you're thinking about ordering a used one off ebay?
 
another option for the MIDI and SPDIF might be to look at an m-audio Delta 66.  the delta 66 is exactly the same card as the 44 but it has the digital I/O available on it and you can use the same drivers as the 44 and they both show up in the panel on the m-audio software (so does the 2496 if you have one of those).

that's true, the D66 doesn't have MIDI, just SPDIF

Just got one of the cheap ($10) MIDI to USB cables.  Works perfectly fine, with no noticeable latency.  So we can forget about buying something expensive!