He-he, if in audio we always say "let your ears decide," in watches, it's let your wrist decide.
First, do you prefer analog (mechanical) or digital (quartz)? There are luxury models of both types. Tag and Omega make new, $$$ quartz models; some vintage quartz watches fetch good $$$ too as collectors items.
Mechanical ones can get beyond luxury. Cost no object, my money (if I ever amass enough) goes to this:
though I much prefer it in white gold or platinum. I'm actually a stainless steel / titanium kinda guy but this particular "manufacture" only encases their movements in precious metals. This one's German, BTW, not Swiss.
There are in-betweens called mecha-quartz like the Citizen Eco-drive. Though in this category, I like the now discontinued Jaeger Le Coultre Mecha-Quartz chronograph (the "scientific" name of a tomepiece with a stopwatch function).
Among the quartz ones, I like those from Polar, Suunto, and Timex as I have fantasies of being a triathlete.
Second, what'll you use the luxury watch for? There are dress watches
Dive watches (The Omega Seamaster, popularized by James Bond being a quintessential piece, IMHO. Actually, James Bond also wore a Rolex but I don't really fancy that house...more later)
Sailing watches, watches originally designed for playing polo (the art deco) JLC Reverso series, etc.
While many golfers and tennis players endorse luxury watches, I can't think of any practical, i.e., non-image reason why you'd use a luxury watch while playing those sports.
Third, what complications (features) do you want on the watch?
There are simple second hands, date, day, month, year, etc. Mechanical perpetual calendars are fascinating since they know leap years, which month have 30 days vs. 31 days, etc. without using any bit of silicon.
There are the chronographs, my favorite being Zenith, the first mechanical watch that meaures up to the 10th of a second. The popular (especially among the Japanese) Rolex Daytona once sported a Zenith movement which Rolex "downgraded" to their own specs--they didn't want the ability to measure up to the 10th of a second.
My personal favorite complication (though I don't own one) is the reserve de marche or RDM if you don't want to bother with the French pronounciation. It gives a guage how many more hours you still have left in the spring winding of your watch.
There are also moonphases...probably useful if you fish.
I travel a bit for work so I very much like worldtimers. Vintage Dog likes Patek Philippe, I particularly like the Twenty-Four.
Third, there is the price consideration. Oris makes fine pieces at the US$600 mark. I have their Worldtimer.
IMHO, the next significant price range is the US$2k mark where you get Omega. US$3-4k takes you to the Jaeger le Coultre range. US$10k takes you to the top tier of Pateks, Audemars Piguet (Governor Schwarzenegger's choice), A Lange & Sohne, Vacheron Constantin, etc.
Fourth, the Swiss ain't the only ones with watch making expertise. The Americans have Hamilton, Russians have Poljot, Germans have A Lange & Sohne, Italians have Panerai. The Chinese and the Indians have their own brands too.