New to classical music

Another is The Planets by Holst. Have to agree with Elizabeth, Brahms may put the op to sleep. Approach him after you have digested Beethoven and Mozart.

Surely Tchaikovsky Piano Concerto no. 1.  The other warhorses: Schumann and Grieg piano concertos.
Then some Wagner overtures and orchestral arrangements of excerpts.

Search for Denis Matsuev on Tidal. Pick a Tchaikovsky or Rachmaninoff, turn up the volume and enjoy

I could be wrong but I think the OP was saying that his OVERALL musical tastes are pretty eclectic, not that his tastes WITHIN the classical genre are eclectic. So maybe start with recommending large scale orchestral works and piano compositions that are a bit more accessible than Part, Stravinsky or Bartok? Showing my age here but my interest in classical music was stimulated by the film "Children of a Lesser God". There are two points in the film when William Hurt tries to decompress after a long day and puts on the Adagio from Bach's Concerto for Two Violins. I had zero exposure to classical before that moment and it sounded so lovely I went to the local record store (Melody Records Dupont Circle in DC) and bought Trevor Pinnock and the English Concert's most recent recording (on CD). I moved back to NJ months later to work on my thesis--hours a day for nearly a year--with WQXR on the radio and the listeners guide on my desk. Every time I heard a piece I liked I highlighted it in the guide and then brought it to the record store with me to guide the building of my collection.

edcyn, thank you for bringing up Pollini, I lived in NYC a long time and saw/heard him multiple times at Carnegie, I still search the internet for concerts he might do in my area, he is wonderful, thank you for jogging my memory! I have many of his (DG) records and CDs, and this prompts me to get them out and revel in the beauty. Thank you again!