I really enjoy my DSi especially during downtime while in groups. If I could go back though I may have picked up a PSP instead just for the access to easier/superior ROM emulation for SNES titles. However after checking out that link to the R4 chip it seems I may have to change my opinion as SNES emulation looks completely possible on the DS. A quick google search lead me to this article about it:
http://nineoverten.blogspot.com/2007...ntendo-ds.html . So thank you for the link above grindle!
There are some decent RPGs out for it now and as mentioned above the FF series is slowly being updated and re-released for it. I played through FF 4 many times both on SNES and emulation and the newest rendition of it for the DS makes it feel like a whole new experience.
I would really recommend going for the DSi over the regular DS as the price difference isn't really that HUGE and you get bigger screens. I saw a commercial the other day for an even newer version of the DSi with a bigger screen so that may be something you might want to look into.
The wifi is nice but if you are some where that makes you load a website first and agree to a TOS to connect you may run into some difficulties but I will routinely take it with me around my campus many times for the ease of being able to check facebook and my email while on the go. The camera on the DSi is also decent and can come in handy for some quick casual picture taking.
Overall I would really recommended one if you are thinking about it and if its not against your personal morals pick up the R4 chip so you can enjoy the classics as well.