For web pages, the actual image that ends up being used will display on a screen at 72 dpi. So all the scanners listed will give you the ability to scan and selectively crop for this use. Features, usability and aesthetics would be my only concern if I never wanted to put the scans to a high definition use.
By default, Windows operates at a notional screen resolution of 96dpi (dots per inch). I think that "72" has been inherited from the printing industry. If you print text using a font size of 18pt, it will be 1/4 of an inch high (I think).
If you choose "Large Fonts" in windows, the notional screen resolution in Windows becomes 120dpi.
All modern scanners should be good enough for web use - what's best for you will depend on price, speed and features. Since, features are mostly implemented in software - that's something you should look at. If you want to scan slides, you'll need a transparency adapter (included with some scanners).