Because I tend to have a one-pot rule in the week, I'm a big fan of adding the rice and/or pulses and stock to the meat/fish/vegetables for a complete meal. I generally use a chicken stock, but a vegetable one is fine and of course if it's a lamb or beef meal then a lamb or beef stock is best. Chicken stock's fine with pork though as is vegetable.
I am not great at quantities as it varies according to how hungry you are, but here are some rough guidelines.
Allow approximately 70-80g (dry weight) of rice per person. All you do is add the risotto to the meat/vegetables that are already cooked - and if you're adding wine to a risotto, add that before the rice, too - and then just cover the risotto with stock before stirring in and leaving to simmer (checking regularly). If you DO need to add more stock, do it a ladleful at a time. I know it's not the 'proper' way but it never fails for me.
Long grain or basmati rice
The general rule here is double the amount of liquid to the amount of rice, so 200g rice = 400ml liquid. Anywhere between 80g and 100g (for Absolutely Starving days) is a reasonable portion, erring on the 80g side.
A note on stock
Stock, generally, tends to get made with instant bouillion powder unless I've made a roast at the weekend, and that's fine. However making stock is dead easy. Just strip all the meat you want to eat off the carcass and then put it in a deep saucepan with one onion, halved, 3-4 sticks of celery, a carrot, a couple of bay leaves, some salt and black pepper, and a lemon (I like lemons). Bring it to the boil and then stick the lid on and simmer for a couple of hours at a low heat. When you're ready, strain through a sieve, skim if necessary and if you like you can reduce it down for more flavour. Especially awesome at Christmas - if you don't make stock from the turkey you'll be sorry, because it makes the best stock of the year.
Stock HAS to be hot when it goes in or it'll knacker the whole dish.