Hi Sammy.

Microphones come in all shapes, sizes and prices so it's a case of optimising all three to get what you want. I'm assuming that you don't have thousands to fork out on a microphone.

If you're working in noisy environments where you can get the microphone within a few inches of the speaker's mouth then a dynamic microphone (like the Shure SM58 ) will work well.

If you're doing a mixture of recordings then a hypercardiod or cardiod condenser is a good alrounder. The best value for money are those from Sennheiser such as the MKH50 (very expensive) the ME64/K6 (very good value for money) or the Audio Technica AT3031 or Pro37 (cheaper). The AKG SE391 is also worth looking at as the capsule at the end can be changed, depending on the recording situation (as can the M66/K6).

For video work where you need to keep the microphone out of shot or on a boom, then a directional microphone such as the Sennheiser M66/K6 or the Audio Technica AT835b or the AT897 are good value for money.

The thing is that, with microphones, you really do get what you pay for. Cheap microphones really aren't worth it, you will hear the difference. For value for money "Audio Technica" is a Japanese firm which makes very good microphones at a reasonable price (£100 - £200 for what you want). Next up the quality scale is Sennheiser from Germany but they do cost a bit more (£200 - £300 or more). For dynamic microphones (which aren't as sensitive as condensers) the American "Shure SM58" has a lovely sound and is used by singers on stages all over the world (£100 max).

Edit: It really does depend on what it's going to be used for...