Purchase Advice Needed: XPS, Optiplex or Inspirion?

All of the product lines that you mentioned could be suitable for you. The difference comes in how you choose to equip them.

The XPS model line is intended for home and home office users. It uses premium quality parts and construction. The Studio XPS 8100 I'm using for this message is more than 13 years old and still runs well. In general, XPS computers are built for high performance, but not for the most hardware-intensive workloads, which are better-suited to a Precision computer.

Optiplex computers are designed for larger organizations with professional IT administrators.

As a result, they are built with features that are useful to an IT department.

Inspiron is an every-person's computer, with an emphasis on value. Inspiron computers have middle-of-the-road parts and build quality.

One more thing to say about all these computers: Dell PCs are not designed to be easily upgradeable. You'll be able to add RAM and hard drives, but anything other than that will be a challenge. That's because these computers use small cases with proprietary motherboards.

You must look at each specific model with an eye toward your priority list.  More and more pre-built systems (in other words, all of the ones you've mentioned) are becoming more like  appliances than the PCs of the past.  Between the small cases, proprietary components (including the mainboard, case and power supply), and the lack of expansion  slots (many new systems have only two memory sockets now), there are plenty of roadblocks to future upgradeability.  If you need space for an existing 3.5" hard drive, even that's starting to disappear -- many cases won't take them now.

You may also want to consider the other option:  either building a system yourself, or having one built for you by a local shop or a boutique builder.  The advantages of a standard sized case, mainboard and power supply, together with a more extensive feature set on a standard ATX or even micro-ATX mainboard, cannot be overstated in light of the ability to upgrade later on.

@Bulldog​ I'm leaning toward another XPS desktop but I want a graphics card that is quiet and cool running since I don't plan to flex the muscles on this hardware.  I hate slow, hot, noisy PC's.  My 11 year old XPS8500 runs cool and way faster than my wife's 7 year old XPS8910.  I never pursued the issue of her slow PC because she doesn't seem to mind and it could be she simply loaded too much bloatware.  The point is I don't want to get stuck with a lemon but I want to move to a new box with Windows 11 before my current machine takes a dive.  I am heavily dependent on my PC for personal business and finance.   

@ejn63​ ....more like an appliance....  With that in mind, I'll try to get what I think I will need for many years to come and not bother with much future upgrading.  Last resort will be to buy another 'appliance' down the road if there becomes a pressing need for it.

@GeneInFlorida​ 

" ...  I want a graphics card that is quiet and cool running since I don't plan to flex the muscles on this hardware."

Same here. I'm not a gamer, so I chose the GTX 1650 SUPER, to take the burden of processing graphics away from the CPU.

Like you, I am also heavily dependent on my PC for personal business and finance, so I chose an XPS computer.

P.S. I would love to learn how to make paragraph breaks with line spaces in the new software that Dell is using for its forums.

Perfect question--TY--me almost exactly. Sorry I know old thread--but this really helped--Inspiron, XPS, Optiflex in price order--I'll prob go with XPS because of this chat. I have an old Optiflex, but it's terming out on Win10 so have to junk it. It's been great, and wld never do anything but Dell. The previous user of this Opti was a professional bond trader and needed 3 monitors plugged in at once. I don't need that kind of firepower.  Thank you again!