It turned out to be the Samson CO1U USB Studio Condenser Microphone that I had ordered from Amazon... and here is it set up with my laptop in all it's glory.
It being only around £70 for a proper professional microphone, I honestly didn't know what to expect from it, but I'm actually really impressed. Assuming you're close enough to the microphone, or the noise you make is loud enough, there's barely any background hiss at all, despite all the horror stories I'd heard. It makes sense I suppose- if you have to increase the volume of the singer, you have to increase the volume of the background noise too.
Renee and I also covered 'You're Gonna Go Far Kid' by The Offspring using the new microphone on Friday, which you can find on Youtube here. Beware, there's a fair amount of bad language in this song!
Another bit of band news, we've started talking to a couple of other people about forming a proper band (as in singer, guitarist, bassist, drummer) and we may be starting something on that front- but it's still probably a long way away.
Thanks for reading!