bbither
Like Joel, I bootstrapped a software company to similar size (25 employees). I did a calculation and we spend about 1.4% of our revenue today on 5,000 sqft of office space, but have outgrown it and it's no longer the nice spacious office we started with. 10,000 sqft of space in the best class A space in Western MA will cost about 3% of our 2009 expected revenue, with modest but nice build-out included. Given that this would be our 4th move in 6 years, I tend to be careful about long leases and lease buildouts.
I'd rather invest in paying good salaries, offering the best equipment and a nice (but not extravagant) work environment. Then I can afford to launch new products without being beholden to investors.
I really like the glass walls though...