For order and structure, you would be better off with music from the Classical period (not to be confused with the generic "classical" music by which people generally mean "cultivated" music as opposed to "vulgar" or "vernacular" music) such as Mozart, Haydn and early Beethoven to name some big names. If you are drawn toward the Baroque period, CPE Bach is a good bridge between the Baroque and Classical periods. The most effective are going to be the pieces or movements with the most structure so look for rondos and first and last movements of sonatas, particularly solo piano sonatas. (The first and last movements are usually the most structured, being either in sonata-allegro or five- or seven-part rondo form.) If you like chamber music, piano trios and string quartets and quintets can be nice too. I would steer clear of concerti as the change in instrumentation from orchestra to solo play is distracting to me.

If you are interested in less tonal music, dodecaphonic/12-tone pieces and pieces such as Bartok's Music for Strings, Percussion, and Celeste offer some of the most rigidly imposed structure for music. It isn't tonal in the traditional sense of the word, so it could be rough on the ears. It might help to read an analysis if you are in any way familiar with music theory.

Since the key is the actual musical form of the piece or movement, it can be difficult to track down the best stuff but you should be able to compile a good list of tracks over the next several weeks.

Audio Hijack can do this or iFill from Griffin can do it as well.