Unless you have a compelling reason to choose a desktop/tower form factor computer, my advice for most people is to move to a high grade laptop form factor.

A USB 3.0 docking station provides lots of connectivity, with lots of different docking station brands and models available.

The laptop form factor eliminates the need for a UPS since the internal battery can provide power for several running hours. Laptop is highly portable, making transport for repair easy or just the ability to use it elsewhere in the house or beyond.

External display connections are common, and often there is provision for two or even three external displays. External keyboard and mouse connect just the same.

Compute performance has become more than ample for all but top tier heavy duty work. Even video editing is entirely reasonable. Heat output and energy consumption are typically a fraction of desktop.

Switch to large capacity SSD internal storage wherever possible. The speed is impressive, with no sensitivity to mechanical shock. Longevity is more than good enough among the better makes.

The challenge is to choose wisely from the available products. Personally I have become a major fan of the qualities found in current top tier Apple laptops. The overall MacBook Pro package is quite well made and price competitive with similar, if you can even find similar across the 'Only runs Windows' competition.

For me, an interesting advantage is that Macs can run Windows, and run it very well. But Wintel machines cannot legally run Mac OS X. With a Mac I can run either or both of the most popular operating systems, with support . Or I can run Mac OS and Windows together, at the same time.

With Wintel laptops, running Mac OS is only available via a hack.