The earliest set I've bought did not have top-end chips big enough to handle the growth to the game. This led me to add-ons. Since then I have always gotten one bigger denom than I thought I needed. Better to have and not need...
That said, in my CPC set, the "nicest" chip (Level 9 at a time that there was no level 9) is the T5000, because it would hit the table every game. The T25,000s have occasionally hit the table though, so I am glad I have them.
My basic rule for putting out the top-end chips is that there have to be at least 3 hitting the table before I put one out. A single T25k popping up during colorups may be easily missed by a less observant player, or "hidden" by one of those people that put big chips at the bottom of a stack. We try to remind players to keep big chips "up front, on top", but since many cardrooms and even more home games permit a single T25000 to sit at the bottom of a barrel of smaller chips, it is an uphill battle to fight.