I know the dilemma jeremicium. It seems that for the last 3 years, there has always been another reason to spend the money, rather than buy a new car.
In fact, I've looked at buying several other cars BMW and not in the last two years, however, I just can't seem to find a car that I love as much as my 2006 BMW 330i with Premium and Navigation; except for my Father's 2007 335i.
I currently have 193,xxx miles on the car and it has been out of commission for the last two weeks. This is been the most reliable vehicle that I have driven. You can surely drive past 100k miles without worry. Once you get to 150k, that is when you should buy a AAA towing membership. My Bimmer first stranded me at about 175k when my water pump failed on a trip back from a job interview in Iowa. Luckily it happened on the 200 mile drive back. Since that time, I've been personally trying to troubleshoot a small leak in the Evap system. If I was less stubborn, I'd pay someone to do the work, but I really have learned so much about the car by now. And I'm too cheap to pay someone $100/hr or more to do the repair.
Finally two weeks ago, the starter failed at 193k. I ordered a started on Amazon (Bosch) for only $100, when the Stealership wanted $500 plus $500 core charge. I'll order auto parts from Amazon for such a savings, especially when they have all the parts I want with quicker shipping and FAR cheaper prices than the Auto Parts stores, Dealerships, or even other Bimmer sites. Customer Service is lacking, so you have to know what you are ordering and search the part numbers. But with Amazon Prime you get two-day shipping included in the Membership cost of $79 / year.
Anyways, I had to take the Intake Manifold off on my e90 2006 330i, there wasn't a DIY so I struggled through this myself. When I put everything back together, I realized that I didn't plug in ONE of the electrical connections in the Intake Control Unit. Like an idiot, I decided to start the car anyway. Replacing the Starter has cost me about $500 in mistakes. I had to buy $200 in Vacuum/Oil Separator hoses and then $300 replacing a broken Adjuster Unit ( Disa Valve ) in the intake because I didn't have one of the units plugged in, started the engine and then broke the adjuster unit with air forced through the intake. I will be posting the DIY and take pictures as I put everything back together. Hopefully this will help someone else save some and money when working on the Intake or the Starter on an E90.
I buy a few things from Bavarian Auto, but they have a VERY GOOD Recommended Service Interval Matrix for your BMW. Here is the Site for all:
http://www.bavauto.com/shop.asp or for the 2006 330i
http://www.bavauto.com/Assets/inst_pages/e90mc.pdf. If you keep up with these intervals, you can rest assured that you know when parts commonly fail. If for no other reason, you can buy the parts on sale and keep them in stock for quicker repair when something does fail. I have found the most time is spent waiting on parts to be delivered.
Long story, Short... If you Love your car, as it sounds you do, hang onto it. These are such impressive vehicles that there are few options on the road that can replace what you have. Except for a newer Bimmer. Good luck in your quest, European delivery would be pretty cool.