Don't get analog cameras, they are so "last year"
Try and find one megapixel IP cameras minimum, if you really want quality!
If Windows is your thing there's free software called J-Surveillance that can record up to 25 cameras (make sure when buying the cameras they are ONVIF compliant), lets you log in with your smartphone (android or iPhone), can text you pictures when there's motion when/where there's not supposed to be, etc.
You can use wireless and wired cameras. The wired cameras can be powered right over the network cable you use to connect them (be sure to specify PoE when ordering the camera), and even if camera doesn't have PoE you can still pull the power from the network cable and feed the camera with it, it just isn't as pretty (called external PoE)
. Of course if there's a power outlet near the camera, you can just plug it into power (they come with power adapters).
For cheap ($57 including shipping)
wireless (camera supports wired too) 0.3mp (i.e. 640x480@15fps progressive scan) cameras I always use these for my customers:
http://www.aliexpress.com/item/Free...twork-IR-NightVision-IP-Camera/449395708.html (doesn't support ONVIF and comes with pretty goofy software to record/alert you. You can use your iphone/android to connect directly to any one of the cameras though, to view it live, works great). They have an absolutely amazing picture for only being 0.3MP, makes ANY analog camera look silly! They are encrypted so nobody could ever connect wirelessly to the camera to see the video.
They have a wide angle 3.6mm lens (approx 70 degrees hFoV) and work great both during the day and at night (comes with I.R. nightvision) and work amazing outdoors and inside too (they are weatherproof and survive the cold perfect and don't fog up).
For my customers that want top of the line, insane quality, I go with this $157ish camera:
http://www.aliexpress.com/item/WDR-Sensor-720P-Day-Night-4x-zoom-2-8-12mm-Varifocal-Lens-Car-Plate-Read-Function/685848710.html
It's 1280x720p@25fps progressive, comes with a super spiffy adjustable zoom lens, can go from retarded wide angle (90 degrees hFoV, great for mounting in a corner!) to tight zoom! Has a feature called WDR which is mind blowing. It stops things like light reflections, the sun, bright windows, etc. from washing out the picture. It doesn't matter if you pointed the camera right at the sun, you could still see the clouds perfectly, that's how amazing WDR is. Once you use a camera with it, you'll never use one without! Supports PoE for easy powering in goofy locations, and ONVIF for great recording software compatibility. I'm setting up one of those exact cameras as a streaming traffic camera for a customer right now in case you wanted to check out the quality (this stream is at half resolution/360p due to my crappy internet upload bandwidth):
http://tafb02.click2stream.com
-Jamie M.