Oh yes. Definitely.

I buy lots of technology stuff, which of course changes constantly. My advice (for what it's worth) is two-fold..

Rule 1: Unless you know or strongly suspect that a significant update is coming - end of model year, etc. - buy it now.

Rule 2. Buy the best / biggest you can afford. That is, don't buy the 32GB iPod if there's a 64GB available now. That way, your product will (hopefully) be somewhat less obsolete when the new one comes out.

Rule 3: if a new model just came out, buy now.

This is such a PITA, for us Apple whores, there's a website..

Mac Buyer's Guide: Know When to Buy Your Mac, iPod or iPhone

It's easier with Apple, though, because they sort of stick to a schedule. It's not foolproof, though. On this one, for example, they say "iPhone: Don't buy - updates soon." Well, yeah, but not for like six months (probably). Of course, it's up to you to decide if halfway through a product lifecycle is "soon" or not.

For the X5, we know the new one isn't coming until AT LEAST 2014. My 2011 will probably have 100K miles by then so it would be TIME for a new one.

BMW though.. Not so much. I'm glad they frequently refresh their product, but I am not used to someone making substantial changes in the middle of a model year. I am used to a car maker introducing changes with a NEW model, not "well, we made four changes to the 35i Premium in the 2011 model year." It's not.. comforting.

A good friend of mine who also buys lots of tech crap is one of those "don't buy anything now. Wait." with the result that so much of his stuff is so obsolete it's useless (won't work with the new stuff).

One slight comfort is that while the PACE of changes is EXTREMELY rapid, the trend tends to be that a new version of a product is usually only a minor change. This is why, for example, I can keep a MacBook Pro for at least two years before a genuine "new model" comes around.

I can set my 2010 model next to my 2009 model and they are virtually indistinguishable on the outside or even when you open the lid. There are faster guts in it, but even still it's not a DRAMATIC change.

(no, don't ask why I bought a new one anyway..)

Cars, thankfully, don't change QUITE so often. I might have bought a used X5, but by Rule 3 (above) I couldn't go wrong.

It's true - you can't win this game. I didn't know that there would be new entertainment options. I MIGHT have waited, but by Rule 2, I hedged the bet a little bit - heeded Rule 1 - and I'm still happy.