Some comments on what others have said above.
1. Canon FD lenses are definitely cheaper than Nikon. If you are into street photography, you probably want a fast medium telephoto plus a versatile wide angle, the 35 is a good choice. I don't like zoom lenses any more, too long, heavy and slow. But used zooms of all brands tend to be cheap on
eBay, while fast primes are bid up.
2. Canon rules the roost now in digital. But through the 1980s, it was the other way, with most pros using Nikon. Nikons have very good build quality, more so than most Canon film cameras. An AE-1 was my first SLR, and it is still in great condition, accurate meter, but it does have plastic parts inside. The "chrome" is really plastic. By contrast the FE (which was $100-150 more expensive in 1980 than the AE-1) is smaller but more solid, with ball bearings where they count and pro level components (Nikon for some reason tended to bring out new tech first in advanced amateur level cameras before they introduced it in their flagship line. True of the FE and also the N90s). If you can get a Canon in good shape cheap, then great. But in quality and mystique, the edge goes to Nikon.
3. Nearly all old film cameras are dirt cheap. You can get a Nikon F3 now in good usable shape for $100 or less. An N90s for $30-45. And these are cameras that ran close to a thou new. Be careful about pro level cameras, because they may be about worn out. Nikon FMs tended to be used professionally, and those I've seen appear to be heavy users. Canon F1s are still pricey on
eBay, and I suspect most are worn out and not a good buy. EBay prices on everything are all over the map, so there is no substitute for watching and learning before you bid.
4. I disagree with some of what was said above about certain cameras. Correct me if I am wrong. The Nikon EM is a small aperture priority only camera with a needle that shows the shutter speed the CPU selected for you. Some film enthusiasts still carry one because they are cheap (<$30) and pocketable, ideal for street photos. If one breaks, small loss. (There is a pancake 50mm lens that makes them seem even smaller.) The EM is plastic on the outside and you think it is a dinky little plastic thing, but I understand it has a solid metal chassis underneath and has some impressive tech under that plasticky exterior. I prefer the FE which has a needle in the viewfinder that shows shutter speed when you go aperture priority, works like a match-needle if you go full manual, has easy exposure compensation +/- 2 stops, and will do multiple exposure. A great thing about the FE and the F3 is that they will take any Nikon F-mount lens, from 1959 on including non AI lenses; not true of later Nikons, which will not mount the old lenses. The Canon AE-1 is not built like the AE-1 Programmable; structurally they are different cameras with the programmable a half-generation ahead but behind the T-70.
5. For me, I like knobs and dials and needles better than LCDs and multi-function buttons. So I am cool with the FE, AE-1, F3, and so on. However, in a camera like the N90s you can buy incredible technology with wonderful viewfinder readouts and autofocus for under $50. I am not familiar with post FD mount Canons.