Power supply at the bottom
Good airflow ( current case has heat spots everywhere )
A good metal case ( hate the plastic feeling )
Thanks in Advance,
Do you have a budget in mind?
As Pengwin mentioned, several Lian Li cases have the PSU located at the bottom. However, the space is limited in the V1000 II and V1100 II: can't use long PSU's. If you want a case with good airflow, I wouldn't recommend the silent series V1100 II: quiet but very hot.
If price isn't much of an issue, the Silverstone TJ07 is a nice case with plently of airflow (comes with 6 fans) and it can hold 2 PSU's on the bottom. This case is all aluminum, but a little pricy.