Yeah don't see the reason for your post but as somebody who is very closely debating the same two phones (slightly leaning towards this but not going to make a decision until I get to play around with both), let me chime in.
Well it is a late 2010 phone lol (I think it released in Europe in November 2010). That is pretty much 2011. I think you are being a little nit picky here. If by "2010 device" you are referring to the Evo, then you would be wrong. This phone owns the Evo (as it should since it is almost a year newer). It has a better processor, more RAM (768 v 512), more internal storage (4GB v 1GB), Super LCD screen, Sense 2.0.. Also with the unibody aluminum casing, this phone looks better than the Evo imo.
It utilizes the current generation of the Snapdragon system which should be seen in alot of phones this year (including phones by HTC, Sony Ericsson, Acer, LG, Viewsonic and probably more). This generation of Snapdragon processors consumes less power than the previous generation (better battery life), has a better GPU (better graphics/gaming) and can be overclocked to run stable at higher frequencies than the previous generation of Snapdragon chips. While it is single core, it is still a very good single core chip (in terms of everyday performance, the best single-core chip according to Smartbench. Tho in terms of gaming, Hummingbird does have an edge).
Also, considering how dual core devices are still very new and not yet optimized to reach full potential (don't get me wrong, Motorola did make the changes they need to make but I think apps are not yet optimized to take advantage of the full potential except for the TegraZone games and last thing I need is games right now since I can get hooked easy lol), I would say that this will still be a very relevant processor in 2011 (and this can be seen by how many of the manufacturers above are choosing to put it in their 2011 devices).
There is always something better around the corner. Today it is dual core, tomorrow it is 3D, day after it will be quad core. This is a constantly evolving technology. Qualcomm makes a processor, Nvdia makes a better processor than that, TI makes a better processor than that, Samsung makes a better processor than that, Qualcomm makes a better processor than that and the cycle is ongoing forever. Maybe some new players arrive to the game.
Not only that, this phone also features the newest version of HTC Sense (first phone in the United States to do so). A nice video highlighting Sense can be seen here-
http://androidforums.com/htc-inspire-4g/267674-new-sense-inspire.html . Personally, I prefer this to MOTOBLUR (which is why this decision is so tough for me). I personally think that this device looks better than the Atrix and the UI looks so much cleaner. I don't think any manufacturer does eye candy better than HTC. They are just so innovative.
And if you care about modding, it has an unencrypted bootloader meaning you are not stuck with Sense. You can try out other ROMs such as Gingerbread (Cyanogenmod 7 available for the Desire HD with all hardware working), stock Android ROMs, other custom ROMs (maybe Sense based but optimized to work faster). While on the Motorola, you are stuck with MOTOBLUR (or MOTOBLUR based ROMs) and the only way you can get a future version of Android working is if Motorola releases it (which is kind of funny since one of the main arguments for the Atrix is how "future-proof" it is).
Wow this really is a tough decision.
Atrix has the dual core processor, 1GB of RAM (tho 768 is more than enough for me), higher resolution gorilla glass (tho Inspire has a 4.3" super LCD and 480p isn't pixelated for my eyes. Plus SLCD is a big advantage), FFC (not too important tho my sister has an iPhone 4 and she is teaching in Africa for a year so I could use it occasionally), HDMI port which outputs the entire screen (that does sound cool).
I would probably be happy with either but I can see myself wishing I had whichever I do not get at times lol (if I get the Moto, I'd probably be wishing I could flash custom ROMs. If I get the HTC, I'd probably be wishing it had the hardware of the Moto).
I should just flip some coins.