Sizifo -- Tri-X works well in just about anything. It really depends on the look you are going for.
Xtol is a fantastic standard developer -- it is very sharp, fine grained, maintains true film speed, and has nice tonality. It is also good for pushing. It is Kodak's most advanced developer, and their best from a technical standpoint. DD-X is somewhat similar, but uses a more standard developing agent (it is a hydroquinone developer, while Xtol is sodium ascorbate).
If you are looking for the old standard, try it in D-76 1+1 (or ID11 1+1). That is the classic photojournalist formulation, and it is one of the most commonly used film/developer combos. It is a great general combo -- good sharpness and tonality.
On the other end of the spectrum, Rodinal is another special case. Rodinal is very sharp, gives a strong salt and pepper grain, and wonderful, irreproducible tonality. Rodinal just has a look -- sharp, textured and great tones.
If you want to keep the grain down, you can try Perceptol, for which you will have to sacrifice some film speed and sharpness, but you will be rewarded with very fine grain.
One final more specialty option would be Diafine. Diafine is a two bath developer that gives fantastic speed (Tri-x is native at 1250 in it), good grain, and a compensating effect (it compresses the highlights and shadows so it is good for contrasty light).