There are only a few things a casual user would need to consider.
1. Wired/Wireless? Wireless is nice, but batteries are an extra headache. If I don’t have a wired mouse around I just use the trackpad, but you might find this convenient.
2. Portable/Regular? You can use any mouse you want with a laptop, if you see “laptop mice” on sale the mice will be smaller, and if they’re wireless they would have a special compartment for you to hide the wireless adapter they use.
3. Price. There are a ton of mice on the market, pick anything in your price range. Personally, Logitech never steered me wrong.
Comfort is the only really important thing. Go out to a store and try a few. Buy the one that feels the best.
Some people might tell you that you need to pay attention to the DPI and the type of sensor, but I think that unless you’re a gamer or a designer you wouldn’t care.
Any new mouse you’d buy would be a USB mouse, but it might have an optional Serial adapter if you’d like to free up the extra USB port. Bluetooth mice might not be worth the extra cost.