I have amassed a collection of over half a dozen HD monitors in the seven or so years I've been shooting HD.
Panasonic:
BT-LH900A. My first HD monitor and the defacto portable HD field monitor at the time and for many years. I still have it, but I haven't used it personally in a few years, now. One of my friends still takes it out on shoots when he rents my gear.
BT-LH1710. My first large HD field monitor. Again, at the time it was "The" large HD field monitor.
BT-LH910. I ordered it as soon as I found out about it. In fact I was probably one of the first to take delivery of this model. Great monitor and very good picture, especially considering it's LCD. Although I don't use it as much as I used to, I still would not hesitate to highly recommend it to anyone that asked. Like all Panasonic field monitors, it's very well designed. Sony still has not caught up to Panny with regards to field monitor design(not talking image/picture quality).
Sony:
PVM-1741. My first large OLED monitor and THE monitor I use on multi camera sit-downs or when there is time even on longer single camera ones. LCD should be replaced with OLED. PERIOD. This monitor is why my Panny 17" just sits in it's case unless I'm on a crazy shoot and we need a lot of monitors, but the picture is judged and cameras matched with the Sony. As I mentioned above about field monitor design, Sony is still behind Panny and this monitor, even with it's great picture, is no exception. It still feels like it'd be more at home in a studio or edit bay than the field.
smallHD:
DP6 (x2). I bought them as on-camera and very small/light field monitors. Great for framing and focus, but the color is pretty much just ballpark.
DP7-PRO-OLED-SX. Bad @$$ and great picture. This monitor is why I don't use the Panny 910 that much anymore. Insane amount of features(that are constantly being updated via firmware updates), touchscreen interface(along with physical wheels for control on the corners), VERY lightweight and compact, oh and did I mention a great OLED picture? I can't recommend this monitor highly enough. I love it. And if you really want it dialed in, AbelCine offers calibration on it and a lot of other monitors like the Sony OLED's, now. I tried to calibrate my Sony when I first got it and because OLED screens are truly black, my meter could not read it. I guess with OLED being out on the market for a while now, software and meters have been updated to handle it.