Old man needs your input on a second monitor for older iMac

If there is a computer surplus store nearby, and you are able to transport something that is relatively heavy, you can consider a large used pro-quality CRT display. A 21-inch CRT (about 19-20 inches viewable) should be able to do 1600x1200 resolution. People don't like CRTs these days, so cost should be minimal, as long as you don't need to get it shipped (very heavy).

The good thing about CRTs is that they are multi-sync. That means they look equally sharp a different resolutions, so you can set it for 1600x1200, 1280x960, 1024x768, 800x600, etc. depending on what you are doing (and how your eyes are doing). The lower the res, the larger things will look on the screen. If you change resolution from the native res on an LCD display, things get fuzzy.

The bad thing about CRTs is that they typically use more power when active and they obviously take up more physical space.

I have a 21-inch Sun-branded (Sony tube) CRT (usually set to 1600x1200) and it is my main display. It has a flat screen that is really sharp. My 17-inch iMac is off to the right as the secondary display.

For a new LCD display, you should look at options with lower pixel density. For example, there are 19-inch LCDs that have 1440x900 resolution. This is the same resolution as your iMac's 17-inch LCD spread out over a 19-inch screen, so things will look larger. I have also seen 22-inch LCDs at 1680x1050, which is usually the resolution on a 20-inch display.

If you want to pick up an LCD, you really need to consider two things:

1) The physical size of the screen (e.g. 24")

2) The number of pixels (e.g. 1024 x 768)

It seems you have settled on a screen size, so I'll move to the second point.

If the screen supports a high number of pixels, relative to its size (a good example of this would be a Macbook with a 13.3" display and 1280x800 pixels), text will appear small, and you'll be using the computer with a magnifying glass.

However, I don't think this will be such an issue on larger displays. My advice is for you to browse the electronics stores asking for demonstrations of particular displays to find out which ones meet your needs. Record the make and model, and shop around for the best deal.

You worked out Apple forums, so you must be quite savvy!

Since you are using other methods to magnify what is displayed, resolution is probably less important. The resolution gives two numbers. The first number is how many pixels fit left to right. The second number is how many pixels fit top to bottom. So if the physical size of the display is larger, each pixel will be a bit larger. Therefore, text and images will appear larger. But the effect is not close to being 300%, so the methods you are using will overwhelm any effect from getting a larger screen with a slightly lower native resolution.

There are plenty of display display being sold for well under $500 these days. Dealmac.com is a good place to look for deals across the web.

http://dealmac.com/categories/Computer/Peripherals/Monitors/Flat-Panel-LCDs/76.h tml

You will need to note the type of connection used by the display. Some of the cheaper ones may only have a VGA connector. If it has VGA only, you will need this adapter.

http://store.apple.com/us/product/M9320G/A?mco=NDcxOTM0Mw

There is nothing wrong with VGA (CRTs mostly use VGA connectors), but you will probably get better output (to an LCD display) if the display has a DVI connector, which is digital (VGA is analog). To connect over DVI, you will need this adapter.

http://store.apple.com/us/product/M9321G/B?mco=NDcxMTE5NA

There are some newer cheaper displays that use LCDs designed for HDTV sets. They have 1920x1080 resolution. Some of these displays only have an HDMI connector. HDMI is used on HDTVs. You can use these displays with yet another type of adapter, but it would be best to get one with DVI, if possible. But if you want to get one with only an HDMI connector, please post back.

LCD monitors are fixed resolution. That is, the monitor supports exactly a certain number of horizontal and vertical pixels and nothing else.

Your iMac can support up to 1920x1200.

I would recommend that you go to Staples, Office Depot, etc. and buy the 23/24-inch monitor that looks best to you.
For example:
Staples has HP W2338H 23.3" Widescreen LCD Monitor (1920x1080) for $250
Office Depot has LG W2600V-PF - LCD display - TFT - 25.5" (1920 x 1200) for $490
Office Max has Acer x233hbid 23" Widescreen LCD Monitor (1920x1080) $190
Best Buy has Samsung - 23" Widescreen Flat-Panel LCD HD Monitor Model: P2370 (1920x1080) for $270