O-mom makes a great point, you might only want to buy 1 'forever' seat, but the reality is that you will likely end up with more.
I really loved the Britax BLVD, as far as fit, side-impact protection, comfort and ease-of-use. However, as tall/big as my DD is, this would NOT have been her only seat (it was totaled in a car accident last year) She was probably going to outgrow it by height. I considered buying a Tru-Fit (I think it has a higher height limit), but DD was already Forward Facing at 21 months because she was over the weight limit and I had no need for her seat to be a convertible. So, she is now in a Graco Nautilus (which harnesses to 65 pounds, has a good height limit, then converts to a high-back booster - but is NOT a convertible, it's FFing only). It is much more likely that the Nautilus will be her "forever seat" than the BLVD.
I have no idea what your future plans are, but if you think it is likely you will have more children, keep in mind that a seat that will fit a newborn to 2 year old can be used again for future children, as long as it hasn't expired.
Kerri
I guess after all these years of being a Packers fan, I've also got to start cheering for the "Niners"...
DD 11/09/06
DS 06/09/09