Firewire ports Vs USB ports

Most USB 2.0 hubs should work with old 1.1 ports. Just read the specifications; it should say something like "backwards compatible with USB 1.1." Just make sure it's a powered USB hub. That means it has its own power supply and does not rely on the bus power coming from the USB port.

If you have an Apple keyboard (and some third-party keyboards), you can plug the mouse into the keyboard, saving you one full-power port. The USB ports on the keyboard should be considered low-power; a mouse does not need a fully powered port.

FireWire is generally used when a high-speed connection is required, such as with hard drives and video cameras. However, USB 2.0 is almost as fast as the regular FireWire 400. In your case (with very slow USB 1.1), you want to save the FireWire ports for high-speed devices.

If you use a device with USB 2 on an older Mac with only USB 1 it will still be compatible and work, but of course at USB 1 speed.
With only USB 1, making use of Firewire will be much faster. It is the preferred connection for external drives. As far as hubs go, they are basically just a connector so you can't go wrong there. The USB 1 or 2 is the hardware in the computer and the device, so any type of hub will suit. Whichever device you plug in, it will run at USB 1 on your machine.

I don't know who you are directing your question to, but I'll attempt to answer your follow up query.

Your thinking is correct, about low speed devices using USB because the speed of Firewire is not required, but also because USB tends to be a now conventional universal connector. Though today, all computers have both, but your G3 having Firewire was quite a trend setter in its day.

Printer data transfer is slow and USB is more that adequate though they have USB 2 only because everything is USB 2 today. Most memory sticks are overwhelmingly USB 2 which is about the same speed as Firewire anyway. Though as mentioned a USB memory stick for your G3 will run slower.

Save your Firewire ports for a future external drive or video camera, and make use of the USB, as so much is made to run in USB.

There are FireWire printers, but these tend to be expensive specialized printers, like large format printers. Most consumer printers these days are USB.

There are FireWire flash drives

http://www.kanguru.com/fireflash.html

But they are expensive compared to USB flash drives. There are also FireWire memory card readers, but again, more expensive. In your case, if you really need a high-speed flash drive, you have to get a FireWire flash drive because your iMac USB 1.1 ports are so slow. You can even boot your Mac from it, if it's big enough to hold the OS. For people with USB 2.0, it's much cheaper and almost as fast as FireWire to get a USB flash drive.

I don't know of any FireWire input devices (keyboard, mouse, etc.).

USB hubs are pretty cheap, even the powered ones. This one from Belkin is only about $20 after the $10 rebate (and it has seven ports).

[Belkin Hub on Amazon|http://www.amazon.com/D-Link-DUB-H7-High-Speed-7-Port/dp/B00008VFAF/ref= sr 12?ie=UTF8&s=electronics&qid=1217253076&sr=1-2]

Flash memory devices, printers, keyboards, and mice are all designed for USB ports, so you don't need FireWire ports for them. I've only come across one manufacturer of FireWire memory sticks, and the price is about 5x-10x that of comparably-sized USB memory sticks. A USB 2.0 flash memory device is backward-compatible with the slower USB 1.1 bus speed, which still provides acceptable performance for these convenient data storage devices. When connected to a USB 2.0 port, the same flash memory device is incredibly faster. The FireWire port would be best used with an external hard drive or optical drive, like a DVD±RW burner.