Paul, I also replied in your review thread, sorry to hear about the accident. With the car's considerable weight bearing into the wheel during impact, frame damage is probably a given.
In terms of your car list, I agree with Ted - why not another E430? You are very familiar with them and know what to look for, many of the known issues can be determined by an educated shopper. A budget of $18K should net a very nice example of one. As stated, a sport model would be a nice 'upgrade' and you could have cash left over to beef up that wallowing stock suspension.
Only thing I would add is that I'm not a fan of the Volvo sedans, especially the larger ones. Drove an S60 as a rental when my 300E was being fixed and I loathed it. The design is aesthetically pleasing but the interior room is crappy and the visibility is horrible, especially if you are on the taller side (I'm 6'1"). The rear window is thin and the B-pillars hide a lot of the usual visual room when shoulder-checking. The handling and performance also left a lot to be desired. My father has an S40 which has been very reliable, but it is a fair bit smaller than the S60 (and presumably the S80).
Not a fan of the Hondas either, they tend to be rev-happy engines and don't have that solid feel on the highway that I like from German sedans.
I'd second the Acura as well.
In any case - best of luck and let us know what you end up with!