Here's the pitch for the Roku 2: it has nearly everything you love about the, including the remote with a headphone jack, for $20 cheaper.
It's a tempting offer. You don't get geek-friendly extras like the SD card slot, Ethernet jack, or the USB port, but those seldom-used features aren't worth the extra money for most buyers. The Roku 2's remote doesn't have a built-in motion-sensing or gaming buttons like the Roku 3's remote does, but there's not much gaming to be had on the Roku, aside from the occasional Angry Birds session. The Roku 2 even one-ups the Roku 3 by including analog video jacks, making it compatible with older, analog TVs.
The real drawback to the Roku 2 is speed. The Roku 2 lacks the superfast processor of the Roku 3 and, while the difference isn't huge, it is noticeable. Zipping through menus has a subtle lag, although it's not that bothersome, especially if you haven't been spoiled by the Roku 3. I tended to notice it the most when using the cross-platform search feature, with the Roku 2 stuttering a bit as I zipped around the onscreen keyboard to enter text.