>>10564460If you want to dive headfirst into the newest thing, Uni just came out. It has a whole lot of wild features and has been well-received.
If you want to start off with something smaller to get used to the idea of carrying around a virtual pet, try either a Nano or a P1/P2.
These three are the easiest ones to get right now. If you're willing to shell out a lot of money though, you can buy an On/Meets, another older color-screen Tama, or a Connection at a stupidly inflated price.