I recently bought a Raspberry Pi 2, a nicer case than I really needed, a 64GB sdhc card, and a good power supply for not more than one of these cost. Going with a smaller SD card and a less-nice case you'd easily save enough to cover a breakout breadboard for the GPIO and maybe a couple of sensors.
Judging from its performance I suspect the original Pi would have disappointed me and been nearly useless for anything I might wanted to do with it, but the Pi2's a nice little device. It's silent and it sips power. The support and software ecosystem around it is well worth a few extra bucks over similar devices (the first time it saves you even 30 minutes of hair-pulling frustration, which likely won't be long after you open the box, you'll be glad you went with a Pi)
That's what I did, too. I want to create a Pi 2 blade server and use it for local docker PaaS (for builds, running tests, etc.), but can't find a good case for that. The dog bone one takes too much space and is too generic.
I'm happy with it, and I can't really imagine a case being any smaller and still protecting the Pi while providing access to its various ports (including the SD card). I'm not really into the see-through case thing, but I couldn't find an opaque case I liked better for the same amount of money or less.
I mean something like this [0], but more efficient as you need an outer enclosure only. Blade-server like would be idea (where the Pis are vertical) with some more efficient Ethernet cabling to connect them to a switch.
Judging from its performance I suspect the original Pi would have disappointed me and been nearly useless for anything I might wanted to do with it, but the Pi2's a nice little device. It's silent and it sips power. The support and software ecosystem around it is well worth a few extra bucks over similar devices (the first time it saves you even 30 minutes of hair-pulling frustration, which likely won't be long after you open the box, you'll be glad you went with a Pi)