One interesting way to do it might be to formally incorporate the [XPND] modifier from the PowerCards version 2 API script. This seems like something that could be nice in base Roll20 for all inline rolls. The above shows (on an unfortunate roll of 1, poor Kenneth) how it displays in Powercards. The Attack line there is the result. The number in parentheses is the actual roll, the next number the sum of all bonuses and penalties, and the number after the equal sign the total. Since there are only three numbers shown here, the parentheses serve as a really nice, easy telltale sign of which one is the roll and the eye can quickly be drawn there...in contrast to hovering over an inline roll, which shows the full formula twice (once to show the pre-roll formula, and second to show the version with the die rolls in it). I love PowerCards, but agree that I'd like to see this functionality in base Roll20--that way it can work easily with Roll Templates and such, too! More than just a simple display preference, this is actually very, very helpful in certain RPGs--for instance, 13th Age --where the precise number rolled is essential information and determines results in detail. That game in particular doesn't just use criticals and fumbles like a lot of other RPGs--sometimes you need to know if a roll was even, odd, or 16+ as well, and some moves even use all of those possible conditions. If someone wants to use Roll Templates rather than the PowerCards API (or if the PowerCards API is not an option for some current or future reason), adding this ability to Roll20 in general would be very nice.
