I am currently looking at getting a new computer monitor, as some rearrangements have given my raspberry pi its own little desk, but it still has to share its monitor.

Here's my requirements:
* Must have HDMI input.
* Must have integrated speakers.
* It must preserve the aspect ration for non-widescreen resolutions (in particular, 640x480 which is a common resolution for older software). Furthermore, this must either be the default or the setting must persist so I don't have to keep changing it every time.
* I would prefer if it is meant to be controlled via buttons physically on the monitor rather than with a remote.
* Budget: I'll go with $200, though I would prefer half that.

Non-requirements:
* 1080p (720p or 1366x768 are fine for me)
* TV capability (I never watch TV, so it's of no use to me)
* Large screen (I don't have *that* much space anyway)
* Smart TV/Monitor features (would not be used, though it would be neat if the monitor is capable of running a custom version of Linux, but not at all necessary)
* Curve (not going to use the curve at all)

Can't think of any anti-requirements right now, but there are some. (Non-requirements are things that I won't use, but won't hurt if they're there; anti-requirements are things that will hurt just by being there, and might even be deal-breakers.)

So, any thoughts? (I have had Sceptre recommended to me; is that any good?)

Can't the raspberry do that?
When I had my previous monitor, aspect ratio scaling by the monitor was done via the Nvidia control panel. On my current one (Dell U2715H) it needs to be set up on the monitor itself (switch 16:9 or 4:3 with the front buttons/monitor menu). No big thing, I just let my graphics card do the scaling.
Nowadays, I prefer to run old games windowed. If find 27" on a desk to big / too close to run something like 320x200 fullscreen.

I can't help you with your question - I'd never buy such a lowend monitor myself. I have a few old ones in storage that would do the job. (except for built-in speakers - I don't want that crap, good audio is usually a requirement for most of my purposes)

I would go pick up a free or dirt cheap one from a recycling centre/depot/spot.

how 'bout this one

ultra thin led 1600x900

https://www.amazon.com/Sceptre-E205W-16003R-Frameless-Speakers-Metallic/dp/B07743412C/ref=sr_1_2?dchild=1&keywords=monitor+with+speakers+built+in&qid=1599343321&sr=8-2

Agreed. This is your best bet. You probably cannot buy a 640by480 screen these days. But there is a good chance to pick one up for free at a recycler outfit. CRT screens are viewed as throwaway these days.

You will probably not get HDMI or integrated speakers from these models though.

edit Maybe a 15" LED would do the job, throwaway items but likely to be DVI or DP/VGA

Does that even exist, a CRT with HDMI?

I will say no but there has to be a compromise. With a resolution that low you have to be looking at an older technology.

An old 15" LCD might be the answer but not necessarily a native resolution that low. You probably won't get HDMI either but you probably will get onboard speakers. I see these kinds of monitors at charity shops for very little money.

I'm not looking for 640x480 to be the native resolution.

What I *am* looking for, on the other hand, is that:
* The monitor must accept a 640x480 signal, and advertise it as a supported resoultion.
* When it does so, the display should be in the correct aspect ratio. Assuming a widescreen display, this would mean black bars on each side.
* I do not want to have to change the setting every time this resolution comes up just to get rid of the black bars. (One problem with my current monitor is that it stretches the image by default, and it does not remember the change to the setting when the resolution comes up again.)

Pretty much everything has an aspect ration setting nowadays, including nvidia and AMD video settings. I'd assume the thing you're using does too, though I guess it never hurts to check and make sure.

You wouldn't want the monitor to do this scaling anyway, they suck at it.

A old used Dell 5:4 (1280x1024@75Hz) might be a good option. I used one with a 5€ VGA to HDMI converter with the Raspberry and it worked just fine.

Most integrated speakers are not that good but some monitors have the option to add a soundbar. Even if you dont want/need the increased sound quality, it may open more options.

Can't think of a good reason to use a TV instead of a monitor unless price/size is a huge factor.

Edit: "All-In-One" displays can be a option if you manage to find one below 200$

The monitor will likely go to my desktop, which has an intel i5 4670 CPU and an integrated GPU, and runs Linux (it has never seen Windows).

The currently attached display will then be used for the Raspberry Pi 4, and possibly NES/SNES/Genesis Mini or whatever other miscellaneous device I run across.

Edit: Note that the desktop has cooling issues, so it can't get anywhere near full performance for any decent amount of time.

Anyone looking for a new monitor i'd suggest waiting to see if the surface studio monitor that's suppose to come out end of 2020 will be stand alone.
4:3 aspect ratio what 5k? monitor.
Anyway touch input, artist grade colour rep, only downside will be 60hz, but at that size and unless you're playing esports professionally which lets face it YOU AREN'T it will be awesome; especially considering that most titles these days are vertically locked (like grim dawn) meaning widescreen is a total waste.

Either that or wait for FALD monitors to drop in price which may take 5 years or more.

I just googled and Intel GPUs have aspect ratio selections as well, so just tell it to maintain the native aspect ratio and you should be good. If they have integer scaling use that too.

That depends on the monitor. My rather old monitors are very good at it and I would not want the graphics card to do the scaling. But they are not of interest for dtgreene as they neither have an HDMI input nor speakers.

How do I do that under Linux?