I’m writing here based on past discussions with an associate who worked in the radio business before the industry imploded. Formal research routinely finds that familiar content is preferred over unknowns.
Music choice depends heavily on the ages and backgrounds of your visitors. Most people listen to mainstream music, and they know what was pushed on them through TV, radio, background music in restaurants, etc. The bulk of music today is driven by vocals, and interest in instrumentals has fallen across the last 100 years. Pop vocals were recorded technically very well from the 1950s to the 1970s, and then took a gimmicky turn in the 1980s and entered Auto-tune hell by the 1990s.
For older visitors: Consider standards and the Yacht Rock genre. “You probably won’t go wrong” with Paul Simon, Neil Diamond, The Carpenters, Carly Simon, Frank Sinatra, Tony Bennett, Peggy Lee, Elton John, Steely Dan (per recording excellence), etc. Watch out for dated productions (Bonnie Tyler, Whitney Houston, Joe Jackson, Howard Jones) and outright weirdness (Tori Amos, David Bowie). Queen has surprising commercial strength today, surpassing even The Beatles. Avoid political and explicit content. I put Paul Simon’s Graceland of 1986 as the last mainstream traditional vocal recording…then Cher’s Believe happened in 1998…see next section.
For younger to middle-aged visitors: Consider that 1998 is 23 years ago. Believe made weird, warbling vocals mainstream and a great deal of “safe” pop came to rely on artificial processing. So, you are not showing off your speakers but what Auto-tune can do. Most recent “Top 40” content won’t impress. For an office…no Grunge, no Hair Metal, no Nu Metal, no Hip Hop… Perhaps Coldplay (as utterly inoffensive and mild), Radiohead (The Bends or later), U2, Norah Jones (retro-style quality vocals). As much as I personally hate her music, Madonna is a pretty safe choice. Lorde and Lana Del Rey (but beware explicit content) are mainstream and distinct female vocalists. If you have younger adult visitors, consider folk/acoustic such as Fleet Foxes (e.g., reverb-and-layering heavy debut album 2008) or Rodrigo Y Gabriela (self-titled dual acoustic guitars, remastered edition – the original is way too hot).
If following my own tastes, I’d skip much of the above and focus on obscure and more technical stuff. I won’t, because you must appeal to a general audience. In this era, most people have a music app on their phone so they might choose and stream what they like. It’ll probably be mediocre and not reveal much about your speakers, but it’ll be reproduced well and they’ll like it because they know it.