Invest in EF (not EF-S) lens first - you can then migrate the glassware up to any Canon EOS body.
If you bought a 50D you would soon find resolutions issues & need to upgrade your lens.
Good glassware is always the better investment as the technology does not change as rapidly camera body i.e. sensor/processor technology. I have a 40D & wait to see a significant improvement in the dynamic range of sensors before buy another camera body - so the current plan is to invest in L series lenes when I can put the money together
