Be tough on yourself, pick just one, the one you love the most. Say how or what you use you car for to place your favourite mod or accessory into context.
Eg My car is set up for long term remote area touring. It is relatively heavy & to save damage from 'going hard to get through difficult terrain I got an e-locker in the front diff. It has suited my purpose perfectly. I love it. More often than not I flick it on 'just in case', but now & then it's obvious it's needed. Eg towing going south to north of the Old Coach Road, Cape York. It felt like a bit of a 'luxury' when I was paying for it, but it puts a smile on my face every time I use it.