Regular maintenance items are a constant issue, not related to cutting losses....

Personally I would drive it until it's completely dead.. the kbb on my car, a 2001 x5 3.0 basically never goes below ~$6400 (even when the mileage i input is 350,000) .. If over the course of ownership I spend less than that and I can drive it for 100,000+ miles it's worth the investment.. that's just me though, to each his own, if I had the money I would surely upgrade to the e70 :)

Ultimately 1200$ repair < 35,000$ car, dealer fees, initial maintenance, tax, interest rate etc

PS the high mileage with minimal maintenance I attribute alot to the L6 engine, it's rock solid and I've saved myself atleast 1 serious repair in not having the self adjusting air bags, I'm not sure if the 4.4 or 4.6 retains it's value as well..