Who here is still using the x86 in their server farms?
What do you mean, "still"? I imagine most people are using them. Why? Because they're cheap and, most importantly, standardized.
I'll admit, I'm a big fax of Unix, but we decommissioned our last pSeries server a couple of years ago. The last straw was when we tried to add some additional disk space to the machine. Our distributor wanted about $25,000. After a little research, I discovered we could get a whole new x86 server with twice the disk space for less than $18,000. I'm pretty sure it was more powerful than the pSeries system. too. For the price of an IBM pSeries or iSeries machine, you can get a couple of x86 machines and use the second one for a backup.
Also, when you're dealing with IBM, you're locked into IBM. I suppose I'm not surprised that you can't just drop any old PCI card into an IBM system and expect it to work, but very few non-IBM SCSI peripherals worked with the system, either.
I hated to give up on IBM, but they're just too difficult to work with, any more.