A list of hardware you should think about using:
(General rule of thumb: You get what you pay for…)

Invest your money wisely, and purchase quality rather than quantity. Great hardware lasts a long time, as long as you take proper care of it.

For Students:

Get a laptop, preferably an Apple MacBook
At least 4 Gb of RAM
13-15 inch screen

For Teachers:

Get a laptop, preferably an Apple MacBook or upgrade to MacBook Pro
At least 4 Gb of RAM
13-15 inch screen

What I use on a daily basis:

15″ MacBook Pro, 2.53 GHz i5, 4 GB RAM, 500 GB HDD (2011)

iPad2, 32 GB, WiFi only

iPhone 3GS, 16 GB, WiFi + AT&T

13″ MacBook, 2 GHz Intel Core Duo, 2GB RAM, 300 GB HDD (2006) <– about to retire…