Power Mac G5: A common dilemma: to upgrade or buy new

Question

I know there are a lot of discussions on this topic going around, but everyone's needs and uses are different, so I'd appreciate any input on my situation.
I own a Dual 1.8 GHz Power Mac G5 with only 1GB RAM and a failing 160GB hard drive.
At this point, I basically only use this machine for web browsing, iTunes, and Garageband, and am running Tiger.
I had been having some major hard drive problems so I wiped my system and re-installed Tiger , importing everything from my iBookG4 (which, I recently dropped and the screen connection has failed and is unusable except for as an external hard drive in target disk mode. it is probably too expensive to fix for what its worth so I will probably try to sell it for scrap).
Anyway, everything was ok for about a week until I opened firefox and noticed all my settings and bookmarks were gone. When I restarted my computer, my music, pictures, documents, and movies folders were all unable to be located (although my applications were fine and my hard drive still showed that the space was the same). I'm not sure if I imported some problem from my iBook or if my hard drive was just messing up again, but I've decided that I either need to upgrade or get a new computer.
Basically, I am thinking about upgrading my memory, getting a new hard drive, and upgrading to leopard (mostly for time machine). Or, possibly getting a new iMac or waiting a bit and then getting a new iMac or even (gasp) a PC (highly unlikely).
I was going to get the memory from ramjet and I was thinking of only adding 1GB to make 2GB but could be persuaded of getting more but 400Mhz DDR memory is a bit more expensive than other types. As for the hard drive, I was thinking about getting a Seagate Barracuda 7200.10 SATA 3.0Gb/s 320-GB Hard Drive with a 16 MB cache. I could pay $15 more for a 500GB with 32 MB cache but i really don't need the space and am unsure whether the cache will really help much. Seagates used to have a pretty good rep I thought, but now they seem to be getting mixed reviews, so I don't know.
Obviously, I am no computer expert, so any help would be great. Would it be worth it to spend between $250 and $325 to get the memory, drive, and leapord when I could maybe sell my G5 and my 23" apple cinema display (the old clear kind) and get an iMac? I could maybe get about $700 - $800 for the G5 and around $300 - $350 for the display. Will an iMac be faster than my G5 with the upgrades? I don't think I need a mac pro for my current uses.
Thanks for your help. Feel free to offer advice on what to do with my iBook too.
-rhineth

Answer 1

Memory: $60 for 2 x 1GB, I'd call that very affordable.
http://eshop.macsales.com/item/Other%20World%20Computing/3200DDR2GBP/
Disk drives: 2 x $69 for pair of WD Caviar 640GB
http://eshop.macsales.com/item/Western%20Digital/WD6400AAKS/
It is not about capacity as much as speed and quiet, cool, and how well it handles OS X. I use half the drive, other half is unformatted free space. I'd skip the Seagates. 7200.11 is current.
I expect new iMacs in '09 as they are overdue.
Hard drives you keep or put in FW case.
Current Leopard is 10.5.4 DVD but would be nice to see another DVD now with 10.5.6, $109 (Amazon, maybe less Newegg?).
iMac vs others:
http://www.macworld.com/article/133467/2008/05/imaccomparison.html
http://www.barefeats.com/harper7.html
http://www.barefeats.com/imp02.html
Sounds like three things you may not be doing or have:
SuperDuper for backups. You don't need Leopard.
Disk Warrior. Everyone, or I should say "HFS+" needs #1 disk repair utility.
Backup drives. Two backup sets you switch between, and a small "emergency" partition on one for running Disk Warrior and such.
I replace or move older drives to backup use and put new boot drive in on a yearly basis. Some new drives and memory should be all you need. A couple people even stress their system with graphics and video, and upgrading to 3 or 4 new drives revived their system so that they could hold on and wait another year.