Budget Build

I've more or less got the same thing except ive got a few more parts floating about. I've got some old wheels, the rear of which has a shimano 5 speed (i think) casette (shortly to be removed once i got a lockring remover/chainwhip)...aaaand I was wondering - Is it worth my while to remove the old casette and fit a single speed (im too pussy to go fixed yet) cog with spacers...or should i just invest the money in getting a new rear wheel - probably with flip/flop hub so I can chop up to fixed once I'm ready?

I've also currently got a single 46t chainring on the front - so I figure I can keep this in the interim, maybe (read: definitely) upgrading down the line.

Any advice would be muchly appreciated.

just go fixed. I thought about getting a flip flop but it's just not necessary. Riding fixed is fine and will feel natural after an hour's riding on quiet streets. I now feel more comfortable riding fixed than on my geared bike through traffic as i feel I have more control.