I really want to get the x50 but I'm disgruntled that it has only 520mhz while the x30 has 624mhz. I can't get the x30 because i need the dual slot so will I be happy with the x50 as a gaming machine? Can it run emulations well? Comparably to the x30? Thanks.

You should be. Im happy with my x5(300MHz) for gaming. Emulators should run ok. I don't know about the Playstation emulator. I can't see it running with any problems.
But, In my opinion, The x30 is a better buy than the x50 mid. It has a better processor but doesn't have a CF card slot(It has just an SD card slot). It's up to you. The only difference I see between the x30 high and the x50 mid is looks,Price, and Battery life. So, I would say go with the x30(Unless you need to have the looks of the x50 or you need to have the CF card slot)

I fully agree with cybigamerz, but to answer your question i believe that the x50 is a fine gaming machine. From studies, the only difference you are going to see while gaming is the exact percent difference of the processor speed, nothing less. Since you NEED the cf, then yes, go with the x50 mid.

So I shouldn't be missing out on a lot if i go for the x50 mid. Thanks for your help.

You shouldn't really be missing out on anything(Software speaking). My x5(300MHz) I use for gaming with no problem. So, 520 MHz should be more than enough for gaming.