Sony had NO updates to the PS2? None at all, it is being made exactly the same today when it came out 5 years ago? No new power-supplies? No new anything, DVD drive, anything?
I find it hard to believe Sony never changed anything on the PS2, that there weren't/aren't any differences in hardware (updated models of DVD drives, motherboards, etc.) after all these years.
Now, perhaps, no one noticed, because it didn't give you any new capabilities between each version, i.e. Version 1 and version 5 did the same things, nothing new.
Of course, it sucks that MS didn't include all of this to begin with, and I'm sure they'll screw it up again, when they don't include something else in this version. But if you've already got an 360, this new version will really only be different in that it will have HDMI support (if the stories are correct, you'll still be able to get 120GB drive, and if you 360 works OK now--no overheating--then you really won't notice that big of a difference between your current and this new version). I know that this can be big someday, but right now I wouldn't think it would be that big of an issue. So don't upgrade right now, wait 2 more years, make your current 360 last about 4 years and it will be almost to that magical number of 5 years. Not to mention 360 will likely be cheaper, a newer version will likely be out, and it will be even better.
Besides, your 360 will still be able to do everything it is supposed to, you'll still get updates etc. you just won't have HDMI.
Additionally, it is only a rumor that 360 will get HDMI and internal HD-DVD drive. The only thing MS has said they are doing is processor upgrade to cooler, more efficient design (and even then I haven't seen an actual news release from MS stating this, I've only read it on the net, so even this could be a rumor). In other words, nothing to even worry about right now.