By far, an iMac. It costs $1,200 (schools may be able to get it for less, I don't know), but that includes a built-in 20" monitor, so say it's about $1,000 for the desktop, plus you won't have to pay for internet security. Lots of students are using Macs nowadays, so it's good to get something your students will use (plus it can run Windows if you need). They run VERY well and you can upgrade to Snow Leopard for just $10 when it comes out (which will be VERY worth it). Besides, iWork 09 costs just $60 (lots less than MS Office) and is far superior too, and it's completely compatible with Office. It also has lots of templates that you will find very helpful (such as templates for making quizzes in Pages or organizing your students grades in Numbers). And if you plan to give presentations, Keynote is the best.
around a 1000 dollars
HP TouchSmart 600...
It's the mainboard which determines how much memory you can have.As best we can determine the MSI LGA775 is the mainboard that supports the most memory.It will handle 16GB of DDR2 or 8GB of DDR3.
K10D
The HP desktop printer is only $40, but doesn't have the best print quality due to its price.
In order to purchase a PC desktop computer for under $500.00 you need to watch for sales. Wal-mart, Best Buy and Target would be good places to start looking.
Panasonic GH2
There are a number of retail locations and online stores which sell desktop adapters for this computer model. Best Buy and Amazon, for example, each sell this item.
The best desktop computer to have is a silver sony
The best laptop under $1000 is the light Compaq CQ-50. I have one and bought it from Wal-Mart for about $300 total. It is decent and much better than other computers.
Lenovo y580 i7
Alienware is the best gaming desktop.