For me it is NGC1365 in Fornax - its outreaching spiral arms are visible in my 12.5" scope. It kind of looks like some ninja star ready to be thrown! I agree that M104 is great - easily in my top 10
I have attached a sketch of it that I did last new moon. The sketch probably highlights the arms fractionally more than direct vision does (heavy on the pencil), but the detail in the sketch was all seen at the eyepiece.
ps (its M104 not M103 Mickoking
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