Get some basic Kodak Ultra 400 or Fuji Superia 400 Xtra, both are good general purpose films that are widely available in most supermarkets or chemists and can be processed at pretty much every high street shop in the country.
The only ones that might be a bit difficult without flash is the indoor low light as unlike with a DSLR, you can't just turn up the ISO to 3200 and shoot without flash unless your using a tripod or have extremely steady hands. Night time will mean the same thing.
For specific films for those individual situations my favourite negative films would be:
Indoor, well it: Kodak Portra 400
Indoor low light: Fuji Pro 800Z
Outdoor night time: unsure but I'm sure that Kodak TMax 3200 or Ilford Delta 3200 would be suitable, but if you want colour Superia 1600 (possibly pushed to 3200 although a high street shop won't do that for you).
Outdoor well lit: there are tons of suitable negative films for this job but either Kodak Ektar 100 or Portra 160VC/New Portra 160 would be my choice.
Transparency film:
Indoor, well lit: Fuji Provia 400X (remember that you have to use the relative colour correction filter though if shooting in Tungsten/fluorescent light or there will be a colour cast, the filter will however reduce the effective film speed to about 125 so you may have to consider exposing at ISO 800 and push processing, with colour negative film though they just correct it after scanning)
Indoor, low light: Same as above but exposed at 1600/3200 and push developed
Oudoor night: difficult, will definently need a tripod and likely the same above.
Outdoor well lit: multiple choices for me:
- For landscapes only: Fuji Velvia 50 for its intense colour saturation but don't take any peoples pictures as they will look like their sunburnt
- Fuji Velvia 100: a stop faster for a little less saturation than the 50 and a little more suitable for people but not the best.
- Kodak E100VS: for saturation but much more subtle/natural than Velvia so it can be used in many more varied situations
- Fuji Provia 100F: for a more narural/neutral image and very fine grain.
- Kodak E100G, similar to Provia 100.
Some shops like Jessops do E6 transparency film processing but many need to send it away and it takes about 3 weeks with questionable quality. The best places to get them processed are sending them to a pro lab like Peak Imaging or The Darkroom.
In case you don't understand what push processing is, is where you extent the development time to compensate for underexposure for example where you have exposed ISO 400 film at ISO 800. It does however increase the image grain and contrast and reduce the resolution. You do need to use a pro lab though to do this who may charge a small fee for doing it.
Pull processing, which is a lot less common does the oposite by shorting the dev time to compensate for overexposure by shooting ISO 400 at 100 for example and has the opposite of the effects of push processing.