Depends whether you want something really manual, or a bit automatic.
I started with the Canon FD mount cameras, mostly because the lenses and other parts are very cheap on
ebay (as they wont fit a DSLR), currently use a T-90. I like it as it has tonnes of metering modes, automatic wind and stuff, and can be used in modes ranging from fully manual up to fully automatic (other than focus). Popular ones I know others use are Olympus OMs, they are more manual than Canons I started with.
Not all bodies will offer all features. For example, many canons offered *either* apature priority (Av) or shutter speed priority (Tv), and fully manual.
Either way, spending around £30-£60 on
ebay will get you a well built camera in good nick with a bag, strap, and 50mm lens, maybe a flash, a decent starter kit.
A film EOS would have the benefit of taking the same lenses as a DSLR and they have autofocus, but I dont like the build quality.