Whats your budget? What kind of sound are you looking for?
The magni/modi stack is a cheap amp/dac combo thats been getting good reviews here on head-fi. Not really portable though, if that's what your looking for. The O2 is basically as good as it's gonna get in it's price range. It's popular for it's very neutral sound and for having basically no background noise, allowing you to here the music the way it was meant to be heard. At least thats the way an audiophile would put it I think. In normal terms, it's a good amp.
Imo, if your looking for portable and at home use: O2 amp
If your looking for just at home use I would get the Magni amp and Modi dac, together are about $200. While the o2+odac are like $285. Either option is a good one, I suggest doing a little more research on both before buying. Good research=good choices. I've been an avid reader of this website for the past two years to help choose my audio equipment (which I'm very happy with), and only just made an account the other day :) Research pays off.
Edited by MadMolly - 1/12/13 at 7:33pm