As far as film choice goes, you won't go far wrong with any film from the bigger manufacturers, which are Kodak, Fuji, and Ilford. I second the recommendation for Ilford XP2 if you want black and white, but are sending it away to be processed. It is an excellent film - my favourite ISO400 black and white film, and if you're not using a tripod then ISO400 will come in very handy.
If you are scanning the film, or having scans done by the lab, you'll be able to do B&W conversions in software - so even if you've loaded colour film you're not ruling out mono output.
The "other" suppliers - Maco/Rollei, Efke, Adox, etc - have their fans. My limited experience of them is that handling problems are more of an issue than image quality - by which I mean curly negs which are difficult to develop (for those who develop their own film) and scan, and easy to scratch. Having said that I do use Rollei IR400 for infrared purposes and that one doesn't have the curling problem. These other suppliers are not necessarily cheaper if you shop around.
I find that 7dayshop usually has the best UK prices (once postage is included) for Kodak films, but for Ilford films 7dayshop are expensive unless you but a lot of rolls.
Ilford don't make colour film, so for colour negative film Kodak and Fuji are the main choices.
I've used a lot of Kodak Portra in 160 and 400 speeds. It is excellent quality, with a fairly natural colour rendition. Some examples are here -
https://www.flickr.com/search/?q=portra &w=33186310@N03
I'm now starting to use Kodak Ektar too which has more vibrant colours -
https://www.flickr.com/search/?q=ektar&w=33186310@N03 . Perhaps I will use Ektar when the weather is a but dull and Portra when it's more sunny.
I have only used a couple of rolls of Fuji film in medium format - Fuji Pro 160S and 400H. It's OK but I think Portra has more exposure latitude. Fuji also supply some cheaper films in medium format - Superia and Reala, whereas Kodak only provide their "consumer grade" films in 35mm.
I have found, when using 35mm film, that the consumer grade films can produce acceptable results in good light, the image quality really degrades in low lighting, whereas the professional grade films (Kodak Portra and Ektar, and Fuji Pro 160S and 400H) stand up better in low lighting.