As Bill stated earlier, if you want it now, just go get one if you have the money, don't wait out and if apple releases an update just to find out they've upgraded the ram to 1333Mhz and that's it, you'll think "Why the hell did I wait" on the other hand it could go the other way, but nobody knows.
So as Bill said earlier, just go ahead and buy the 2.26Ghz version now, go grab 4GB RAM from OWC, Newegg, Crucial or somewhere, then you'll be good to go.
As for the HDD issues, it's worth taking a chance. If it doesn't work with the HDD, and you don't want it without it, just swap it back out, and return it to apple for a refund, then wait until you can conclude that the bug is fixed. But it may just be a case of hit and miss as some people I know haven't had this problem swapping out their drives.
Also, you said your machine isn't 'low-end' with a 1.9Ghz and 2GB RAM. I'm sorry to say, but nowadays that really can be classed as low-end. Especially with all the i7's and the soon i5's. For all you know, the RAM in it is only 533Mhz, which sucks.
Regardless of that, just go buy your mac now if you have the money. HOWEVER : If you're not currently enrolled in the college, you WON'T qualify for the iPod rebate or the EDU discounts as people have not told you this. Are you already in the college and just taking a different course in 2010 fall?