Common Cathode vs  Anode in design of LED display

You'll probably want to multiplex the display to minimize the amount of wiring and Arduino pin usage (although you could just do a long string of shift registers in series, since you don't need to update the display very often for a clock).

My suggestion: go shopping for driver chips first, then build the display for the one(s) you like. Years ago, common cathode was more popular, but common anode seems to be more so now.

I have some MC14489s left over from a long-ago project, which are nice SPI-based 5-digit common cathode drivers that I think are still available cheap. I just picked up an SAA1064 that I haven't tried out yet. It's I2C, common anode, that only muxes 2 digits, so I'm hoping it'll be brighter than chips that multiplex several digits.

Somebody posted about the AS1106 a few days ago. It looks like a nice inexpensive 8-digit common-cathode driver, but I haven't tried one out yet.

Ran