There is simply so much more utility (and esp. hardware/software flexibility) in an inexpensive $399 windows laptop it's silly to spend $500+ on one of the somewhat hard-to-find larger portable DVD players. It's pretty easy to find one that's around 9-10" from the major retailers/etailers, but anything larger will set you back some $$$ if you can even find a seller. In the 9-10" size range I've looked at the Phillips PET100, Toshiba SD P2700 and also a Panasonic LX(?)9. Some of the smaller sized players like Sony & LG had better picture quality IMHO.
I'll be straight forward- most of the models w/ 10-11" screens sold @ Best Buy/equivalents are on the junky side for the most part. Their house brand esp. I didn't care for the Audiovox or the Mustek either in the 10" range. Buying them w/o an extended warranty that has a generous return clause would be a massive mistake since failures are so great. Anyway, when I did the research I opted for a somewhat less expensive LG which, although only has a 8.5" screen, I find actually outperforms some of the players w/ larger screens. The picture quality is really good. Built in speaker on the unit could be better, but really, you should be using headphones in either a car or airplane for proper sound experience. Battery life is still an issue on practically all of these players. I ended up finding a Lenmar external battery from vanns.com which extends the life greatly, making it essential on flights/longer car trips. Heck, we made it through four-five 90 minute DVDs until it finally ran out of juice
. Here's the model I ended up with if you can sacrifice size for quality. It's an LG DP781-
http://www.amazon.com/LG-DP781-8-Inch-Portable-Player/dp/B000RWG2JY/ref=sr_1_1?ie=UTF8&s=electronics&qid=1247255025&sr=1-1
Not only does it handle PAL/NTSC, but you can also make it region free with a simple firmware fix via CD (read the customer reviews). Not sure about availability though since it's an older model.
have fun,
Pedro