We bought a similar aged house 10 years ago, got a full survey done, so we knew what we were dealing with. Work we did before moving in was some remedial work where damp had been getting in, complete rewiring, plumbing, heating system, new kitchen, bathroom and redecoration. Since then, we've done very little - replaced the (non-original) windows recently with wooden sashes, but apart from that just normal decoration.
Advice: get a good survey done; get a few quotes (if you keep your costs under control you should be OK for a similar set of work); get someone who'll give an unbiased, qualified opinion.
The big enemy of old houses is water ingress: check the roof very carefully. If there's evidence of extensive long standing damp, then I'd walk away (we did this with one place we viewed: we absolutely fell in love with it, but it had loads of dry rot. We are so, so glad we walked away from that one). Don't go by the damp proofing specialists: there's actually a school of thought that says there's no such thing as rising damp, which they claim to find and fix (it's invariably some other source of damp, such as leaks or condensation, which is relatively easy to fix). What's not easy to fix are the consequences of damp: the wood attacked by wet and dry rot is frequently structural in these houses, so dealing woth it can be very expensive.
Any regrets? none really: we love the house, it's in a very convenient location (as most such houses are), and has huge character. The rooms aren't particularly large, but the high ceilings make a huge difference to how it feels.
Ongoing issues: you have to keep on top of any evidence that things aren't right. We've had a couple of occasions (only a couple, though) of having to pay a couple of hundred to sort out problems that if left would have cost thousands.
One last thing: people say "they don't build them like they used to". This is true, but it usually applies in the opposite way that most think. Poor workmanship is nothing new. Unsound foundations are thankfully a thing of the past, but they do exist in the past, so you need to be careful there too: I'd also walk away from anything that major structural issues, as many of these houses have.
Hope this experience helps.
One final, final thought: if you're the type of person where everything has to be "just so", perfectly straight, unblemished, it's probably not for you. You can get that standard of finish in an old house, but it'll cost an absolute fortune, as you'll have to gut it (and loose "character" in the process). I'm not suggesting you have to live in a place that's full of faults, but the skirting will have knocks in it, details won't be perfect etc.