Wireless N at the moment which is finally out of Draft stage is capable of 300Mbps of transfer. You're more likely to get that speed on the 5Ghz frequencies (with less range on it as higher frequencies = shorter distance but more bandwidth) than the 2.4Ghz because of noise and of course, due to limitations of the technology itself. At the moment I'm running Wireless N and Gigabit over my network. I retired my old Linksys WRT54GX a few months ago. Here, I can get some pretty decent speeds off of the Wireless N Access Point and my gigabit switches hooked up to a Pentium III Linux router I set up. Now, once I upgrade the NICs of every PC on the network and change a few settings in my Gigabit switch and in the Linux router, I can start using Jumbo Frames to lessen CPU loads on the slower PCs/the switch and router. At the moment though, all I have is a 7.1Mbps DSL connection. It's got enough over provisioning on it to peak out at 1MB/s download, and the messed up upload provisioning of 188KB/s upload so even regular Wireless G/100Mbps Full Duplex Ethernet would work out. When Fiber optic internet comes here on the other hand...
Also take note, that as connections get faster, you'll get more overhead on the connection. Jumbo frames do help to reduce overhead thanks to a larger MTU (which means less overhead getting stuck to actual packets). That's why on a 54Mbps wireless connection, you'll most likely under the best conditions peak out at 28Mbps sustained transfer. With a 300Mbps Wireless N connection, you'll peak out at roughly 180Mbps in most conditions.
Otherwise, the iPod Touch Gen 2 I have here is running the 3.0 Firmware. It has no problems maintaining the connection to my network (not jailbroken at the moment). The only time it disconnects is of course when I'm several houses away from my home, or the iPod is switched off/in a power saving mode.
