PCI adapters are generally the best, but USB adapters with an external antenna is okay too. I am currently using a Rosewill adapter with a 5dba external antenna and it's working just as well as my old PCI adapter.
Well if you are going to have many USB things plugged in, like a USB mouse, keyboard, printer, etc. you are going to want a PCI one, because the other USB devices will interfere with the signal.
You can use the console adapter with a computer.....I have this wireless adapter... http://www.newegg.com/Product/Product.aspx?Item=N82E16833340004
Works good for me and never drops signal except for more than 80~ feet away.
A pci adapter with a antenna would be better if you need a longer range.