HP (Hewlett-Packard) 39gs Graphing Calculator
The HP39gs is a great deal at around $50. It does not have a computer algebra system like the HP50g but it does functions similar to the TI-84. USB is supported for uploading programs, and it includes a very fast ARM9 processor. It doesn't support RPN. It will plot in 2D and is expandable with many downloadable programs on the web. The 39gs is quite possibly the best value in the industry right now. Yes, unfortunately it's not as popular as the TIs and maybe not as familiar to some people. It's an awesome choice for anyone on a budget and it looks pretty good physically, too.