2007fp is discontinued. It is popular because it is a 4:3 1600x1200 display, so rotated it matches the vertical resolution of the 30", as well as the physical height (pretty much). The 2007wfp will not match as well physically and will be 1680x1050, so the resolution will be off as well. If you can find them (probably used on ebay or somesuch) the 2007fp will match much better. There is also the chance of getting IPS-based 2007fp's.
I have a 3008WFP and a 2007WFP and the 2007WFP is about 2 cm taller than the 3008WFP.
2007FP is a closer match physically and it's also ideal when it comes to it's resolution, pivoted it has the same vertical resolution as the 30" monitor.
I don't know whether it's a good monitor or not or anything like that, here in Sweden it's insanely overpriced anyway. I'm looking for an refurbished 2007WFP (well, I'm not exactly looking for it, the 3008WFP did set me back quite a bit but knowing that the 2007WFPs aren't made anymore and that another one would complete my setup I'm passively browsing sites like ebay for a good deal )