[villagetinker]

A word of caution on the wireless units. These were used by hackers to cause one of the recent large scale internet outages. It appears the units had minimal security, and default user names and passwords. There was a Russian site that had a large number of security camera IP addresses published that anyone could get to and 'spy' on the users.
So, if you decide to go wireless look into the following:
1. Make sure your network is fully protected, change ALL default passwords, ALL default user IDs, and do NOT transmit your SSID.
2. Make sure your cameras can have security patches updated (under your control only).
3. Make sure your remote login is very secure.
If any of this sounds over the top, remember, that if you do not do these steps, the bad guys could get access to your cameras, know when you are and are not home. Hire a professional if necessary to make sure your security settings are up to date, and to leave detailed instructions so you can periodically change passwords, etc.
Personally I do not trust wireless cameras (a slight degree of paranoia) so my preference is toward wired systems, remember you still need to provide a power supply to the wireless cameras, so with combination cables (coax and power) you only have to run one cable.
On the flip side, wireless are inexpensive ($100 per camera), and wired can be over $3000 for a 4 camera system.
I hope this helps, please do some research, especially on the security aspects of the wireless system.