It depends on what you want it to do. The best internet streamer is probably the
Roku 2 XD/XS but they aren't good network media players.
Netgear's
NeoTV 550 plays most popular formats including MKV and Blu-Ray ISO and supports DTS-HD MA and Dolby TrueHD pass-through. It also plays 24bit/192khz 5.1 channel FLACs and supports gapless playback. But it does not do any Netflix like streaming.
Review
The
latest Western Digital TV Live plays most video and audio formats but does
not support DTS-HD MA or 24bit FLACs. But it does have Netflix (Netflix subscription required) and a couple of others. It's sort of the Swiss Army Knife of media players in that it does a whole lot of things but there are specialized tools available that do a few of them better.
All of the above can be found for less than $100, all support 1080P, and all will work with a Harmony remote. I use the combination of the Roku 2 XS and a NeoTV 550 for as close as I've found to an ultimate experience. Those are the ones that I'm most familier with but CES is coming up and who knows what will be announced there.