OK. My head is about to explode.

I have a Rev. D imac (tray-loading 333MHz) with 96MB of RAM running OS
8.6 and a nifty new 120G hard drive sitting in a drawer and little $$ in
the bank.

I want it to last me at least another two or three years (preferably
five, but let's hope I hit the jackpot before then :-) ).

What my iMac doesn't have is Firewire :::sigh:::.

The only thing I can think of that I'd want in the next couple of years
would be some iPod-ish thing (requiring Firewire) and to rig up a way to
get some VHS tapes and TV shows onto either a DVD or VCD (which I can
play on my iMac if not my DVD player). From what I understand, that
capability will require a G4 processor as a minimum (?). Other than
that, I'm fine even using OS 8.6 versions of desktop publishing
programs, an 8.6-compliant iTunes and my various older
printers/scanners/CD burner.

I figure I have a couple of options (upping my RAM is a must, I know):

1) I see that fastmac.com offers a G4 466MHz upgrade for tray-loaders
for $200US - but I'm still stuck without Firewire. Technowarehouse
offers another G3 upgrade for $249US (but, again, no Firewire).

2) Harmoni offers a G3 upgrade to 600MHz - and Firewire (!) but their
web site says it's $350US. But it's still a G3 processor and I'm not
sure it'll be able to handle some potential VHS/TV transfer stuff (and I
don't have a camcorder and don't expect to get one so I can't jerryrig
something). And I'm wondering what the benefit would be of having a G3
processor when the standard will now be G5s. I'm wondering if a G3 (with
or without Firewire) will be 'obsolete' at a higher MHz faster than a G4
at a lower one. I also wonder if blowing $350US on the upgrade would be
worth it since I imagine I could pick up a privately-sold used 500 or
600MHz G3 iMac already loaded with OS X and a decent-sized HD for about
the same price.

I'm getting confused because I've read too much and too much information
has sludged its way through my brain - I can't figure out if a G4
processor at 466MHz is any better than a G3 processor at 600MHz and
which will be the 'less obsolete' for the next few years.

I also would like to know if anyone knows of a slot-loading iMac Rev. D
G4 cpu upgrade *with* Firewire :-)

My final option is to get a cheap used maxed-out-RAMmed 400MHz iMac with
Firewire for about $270US and toss in a G4 cpu upgrade... know of any
reasonably priced one of those, too :-)

Advice and asperin?

Nick