I prefer 1600. If it's too big you can scale down with no loss.
Remember, screens are getting higher res all the time too
My res is 1440x900 and its still to wide for that. Its just annoying plus I am used to 1200px.
1200 or 1100 px
Usually 1400, I like flirting with 1600 when I have an HQ raw, 1200 bugs the hell out of me.
*Sighs* Conventions. I've ranted elsewhere about this, and I don't feel like doing it again. Let me just utter some questions (possibly bringing this thread back from the abyss of death in the process): Why release based on height at all? Because everyone does it? What advantage does it offer over releases based on width?
Personally, I like to release at 1280px width, when the raws I work with permit it. Some of you will call overkill -- I say, take a look at US comic scans. Those guys do it right. No supposed conventions that hold them back. 1280 (that's exactly the width a large number of users on teh netz use for their desktop resolution, according to Wikipedia) for single pages, 2560 for doubles.
But it doesn't have to stay there (and it doesn't, at least not for US comics)! Scan sizes should grow as technology evolves. Who here wants to read a 1200px height scanlation ten years from now (mind you, your desktop resolution will probably be something like 6400*3600px by then)? Or let me rephrase that -- Who here still uses 640*480px as their desktop resolution?
I use CDisplay to read, which scales things to the height of my choosing, so it doesn't matter much to me. But Ju-Ni's releases have been at 1500 height for a long time. The RAWs I scan are usually slightly over 3000, so we scale down to about half size.
Arguing about this is just pontless. I release with 1200px height, but it's just because it's the standard for my group (except on one Nura chapter when we couldn't clean it ourselves and an international cleaner lend us his cleaning, and it was 1300px height). But if I had to clean for some other group with a different size, I wouldn't mind changing it.
But in any case, less than 1100px height is too small. Actually, I don't like it at all when my spreads get resized because it's mostly hard to read the text. (That's one of the reasons why I prefer MangaToshokan as an online reader, because it doesn't compress nor resize)
I've been using 1100px so far, but I tried 1200px for Azuki and liked it, so I'll switch to that from the next volume of Umishi.
I think anything between 1100 and 1600 is fine, so long as you're comfortable.
I know this has been said, but it's better to scale using width. About 700-800. That might throw off the height a bit if you're reading it. But 700-800 height brings the height to about 1100-1300, you might not be able to see the change anyway.
Now if you scale by height the width is off for some pages. Some pages would be skinnier than others and that wouldn't be very nice to see. Again, you wouldn't really notice it so...
I'd go with 1200 just cause it fits and it's standard. I know Binktopia goes for 1150, so it's kind of a gray area for every group. There's no right and wrong, unless your wayyyy too small to read.