Another vote for the humble CF cards. Nowadays 4 gigs is plenty for most amigas, and they're quiet and fast, rather than having the entire machine vibrate 
There's no way I'm ever going to get close to using 1 Gb let alone 4, so "four times the capacity" isn't really a selling point. Quiet and fast, that I like the sound of. I'm mainly just conscious that my existing HD isn't going to last forever. An industrial grade SSD has its appeal, to me, over a compact flash card which isn't really intended to be used this way. The money isn't that much of a problem (heck I can drink that much money in an evening). The thing I care about most is reliability.
TRIM only needs to come in after you write to the drive a lot. I don't imagine that is ever going to be a factor, either, and even when it does come in it's only to restore it back to original speed. I don't know about this but I suspect the reliability issues with PCs are caused by the high throughput the devices have to endure from modern operating systems.