Hm, that would be a good alternative... If you can live with the performance of a celeron D, anyway. It's not usual celeron crap, it's more respectable, but it's still not admirable by any means.
What you <i>could</i> do is wait for the 925XE chipset and reevaluate the market status by then. I mean, LGA775 celerons with higher clock and based on prescotts won't be too bad at all... and you might just be able to fit a lower-clock P4 with 64-bit extensions in your budget by then...
If I were you, I'd wait. I'm currently planning an upgrade later this year, but I have no idea whatsoever as to what it'll be exactly... 925XE could be good, nForce4 could be good, A64 is nice, P4 with 64-bit is also not bad at all, and has HT, which is an interesting technology from my point of view... But the hardware (and software) market is so messed up right now, that I'll just wait until the dust has settled a bit... For instance, next week we'll see the arrival of 3.2, 3.4 and 3.6Ghz P4s with 64-bit extensions enabled for the workstation market...
<i><font color=red>You never change the existing reality by fighting it. Instead, create a new model that makes the old one obsolete</font color=red> - Buckminster Fuller </i>