Anyone who says cars are not for enjoyment but merely transportation has no advice for me on this topic. To me this is like saying sex is only for reproduction, you're missing the point.
Well said!
jrhampt, these two statements are pretty offensive:
Cars are not for enjoyment; they are for transportation from here to there.
My husband suffers from the same "cars are for fun" delusion
Because you are stating your opinion as if it were a fact. A better way to put it is, "To ME, cars are not for enjoyment, they are for transportation." Assuming that holds true for everyone is delusional. Possibly your viewpoint is skewed due to your husband's spendy ways, but not all gearheads buy new vehicles and let depreciation steal their savings. And we're not poor misguided individuals waiting for you to free us of the bonds of car ownership, we simply like cars. Either be constructive, or consider not saying anything at all.
Anyway, to the OP. 318is's (and really all E30's) have been skyrocketing in price lately, much like CRXs and other cars you listed. It's tough to find a clean one in good shape for cheap these days. E36's are, in many instances, cheaper than E30s. I have found several later 318is, 325is, and 328is in perfect running condition, with maintenance records, and ~100K miles, for under $4K. So consider moving up one generation. Also, I assume you do your own maintenance and repairs? BMWs aren't really that hard to work on, nor are the parts that expensive, unless you take it to a dealer. Admittedly your 540 has a tighter engine bay then other E39's since it has the V8 rather than the I6, but its still very DIY friendly.
The Miata is a great suggestion. Find one in good shape, keep up with the maintenance, and it should last 200K miles plus. Another option in the same vein is the 91-95 MR2s, the non-turbo will get better gas mileage and uses the same engine as the Corolla/Camry, so it'll get great gas mileage and give many years of service. Despite being mid-engine, it actually has more storage space than a Miata. I've owned all three actually (E30 325i, Miata, and MR2), and averaged 27+mpg with the E30, and ~30-36 with the Miata and MR2, depending on city/highway mix. So I've no idea where the 23mpg number jrhampt is throwing out came from.