While the wireless network is convenient, it is often too slow when it comes to streaming high-definition video files from the external back-end server to your front-end HTPC.
Therefore, it is a good idea to get a gigabit router and connect your front-end and back-end systems with Cat 6 Ethernet cables.
Keep in mind that your Internet connection is not going to be faster than 100mbit, but your internal home network will be much faster.
I would suggest to assign permanent IP address especially for your HTPC and/or NAS server that you use as a back-end. This way you will always discover your HTPC from other devices using the same IP address.
If you don’t set a permanent IP address for your back-end computer, the IP address will change potentially every time you need to reboot your router.