Although many chips have full-speed USB 2.0 PHYs (capable of 12Mbps, 1.5MB) built in (e.g. the KL25), I haven't seen another yet that has a high speed (480Mbps, or about 60MB per second). The higher capacity is particularly important for some of the applications I am considering, which use large amounts of SD memory. It also has a full SDIO controller so it will be able to communicate with SD cards at full bandwidth, and I hopefully should avoid many of the problems I ran into using the SPI bus.
The LPC1830 comes with a full development kit and IDE called LPC-Xpresso. Here are some of my notes on getting the kit up and running, and on my first test application - combining the USB functionality with the SD card to make a basic USB-SD card reader.