As the rest of the laptop gets more powerful, more mobile, and more connectible, boot times don't change a great deal. However, Intel has this week unveiled a new technology, "Robson", which utilises flash memory. They've been demoing Robson Cache Technology at IDF.
A "Robson" laptop could have practically instant booting and be quicker at loading applications by at least four times compared to a regular laptop, by using high speed NAND flash memory. Benefits can be had in terms of power as well as speed, with flash memory containing no moving parts, which means lower power consumption.
Flash capacities are increasing, evident by the number of flash-based MP3 players with 2GiB or more storage (iPod Nano, for example). However, capacities aren't at the stage where a user's entire set of data can be stored, so flash may start off being used as high speed system file and program file storage.
It's not clear when Robson will make an appearance, but the appeal is there, and Intel would no doubt like to see an even faster, more efficient Centrino platform. Keep an eye out for flash based storage in laptops... at some point in the hopefully not-too-distance future!