will have a wireless network adapter, and pretty well all of them will come with Windows 7 pre-installed and will have very quiet fans.
The differences arise when you start looking at the processors, the amounts of RAM and hard drive capacities, and the graphics capabilities.
Your specification means that it will probably be better if you configure your own machine with one of the many suppliers out there. Bear in mind that all suppliers are building machines using components that are fairly standard for the industry - it's up to you to do some research and make selections using your own judgement.
Touch-screen technology may look very high-tech in TV cop dramas, but in real life it's not going to set the world on fire - nobody wants to work with a monitor that's covered in greasy fingermarks.