Well, it seems to me that most of what we call options now days actually come standard on many trailers now..........But for me the nicest things trailer have or have available now is:
1. Power tongue jack.
2. Power awning....my bride lives to push that button.
3. Solar Pre-Wire. My rig came with a real stout 8ga. wire pre-wire for solar. I know some come with a pretty wimpy Solar Pre-Wire and probably isn't really worth the $$$, but mine came with real good pre-wire.
4. 4 season package. Every manufacture offers some kind of 4 season package and I am sure there are some that are better than others. But it is real nice to have the holding tanks tucked, heated and protected.
5. LED Lights. For those of us that boon dock oruse un-improved or campgrounds with limited facilities the LED lights preserve the battery capacity and offer stunning lighting.