I nearly went for the SME IV, but it has very variable opinions so probably can't be considered universal. Although, when well partnered, it can be terrific and is very good at managing surface noise, in my experience.
So, perhaps some slightly controversial choices, but I reckon I'd go for either:
Thorens TP90 (particularly the 'S' version), which is soooo much better than you might ever expect, especially if rewired.
Audiocraft AC-3000, 'cos you can't really beat a good unipivot for sheer musicality and the Audiocraft arms are easier to set up than most.
Of course the arm cable also makes a huge difference and best bang for buck surely has to be the Furutech AG-12.
I tend to think of the tonearm as the key component in a turntable, so it's taken me little while to get down to two!
Steph
Sources: Phonosophie No.3 (TP90), Ortofon Winfield, Noteworthy Phonote; Thorens TD521s, SME 312s, Tubaphon Tu-2 blue, Audio Research Ph5; Electrocompaniet EMC-1 UP, Cambridge Audio Azur 851N
Amplification: Pathos Logos Mk1.5
Speakers: Ruark Equinox
Cables: Chord Sarum (various types/ages)
Portable: Astell+Kern SR35, Sennheiser Momentum 2
In the works: Thorens TD124/ii, SME M2-12r; Technics SL-110, SME IV, Audio Technica AT33PTG/ii; Phonosophie No.2 (TP90), Audio Technica AT33Sa; etc...