Honestly, if the game outlives the hardware it was created on, but makes every effort to keep that platform viable for 11ish-years, you can't hold it against them when the platform is finally folded on.
Today is a good time to play FFXI, computer spec wise. For the most part, anything with an i5 is going to run the game beautifully.
The best way to replicate the ps2 experience for a low cost is to go out and buy a cheap i5 laptop with HDMI and a wireless xbox 360 controller (or whatever wireless pc controller suits your fancy, I've seen some newer controllers today that include keyboards built in, if they were back-lit I'd already own one myself). Since it doesn't take much to run FFXI (especially at the lower resolutions that PS2 uses if you prefer that), you could easily get away with a local used Craigslist laptop for around 100 bucks, but I'd recommend getting a new one since they don't cost much more than that new nowadays.
If you get a 'decent' laptop, you'll have the added benefit of being able to surf the web from your couch, stream music for free via things like pandora and spotify, watch netflix and hulu, and my personal favorite as it relates to FFXI, use windower macros for gear-swaps and read ZAM forums while waiting around town for things to happen. You'll also have the benefit of being able to use blutooth headsets for things like ventrilo / teamspeak / etc, if you don't like typing while playing (though admittedly, FFXI is the one game I've played in my life where I actually preferred typing as the primary form of communication, partially due to auto-translate playing such a big role in the game).
So yes, it would suck losing your PS2 capabilities, but if you have the cash for a new laptop, or an old one lying around, odds are you will be better off moving away from ps2 anyhow.
EDIT: Just read Zelduh's response, and I have to chime in on that as well. You didn't strike me as a troll there, but I can see how someone would think you are. For clarification as to why people would think that, you have to understand that FFXI works FAR better on a PC today than it does on a PS2 in almost every regard. Resolution, ability to purposefully oversample textures for a really sharp/crisp look (no jaggies!), very clear text, the ability to substitute call files via simple dat swaps, windower macros, etc, all while still rendering greater distances, details, and quantity of models all at a faster rate than PS2. The experience on PC is just... smooth. Years ago I thought the PC experience was lacking because when I started playing FFXI I was on a very old machine and the game didn't take advantage of graphics card processing power at all... but times have changed and today I am able to run the game at very high resolutions with instant-alt-tabs thanks to windowed-fullscreen mode so I can take advantage of my second monitor etc. If you haven't tried the game on a decent computer in recent years, you really should - it might change your mind if your perceptions are based on older hardware performance.
Edited, Feb 11th 2013 10:46am by FUJILIVES