Reducing the Edit-Compile-Test Cycle
There's a fairly obvious link between developer productivity and the edit/compile/test cycle. One of the big things wrong with Enterprise Java is that you swap the edit/compile/test cycle for an edit/compile/deploy/test cycle and one of the things right about PHP is that edit/compile/test is just edit/test.
I've previously complained about IE7 and the fact that you couldn't install IE7 with other IEs and the old tricks were reported not to work. The issue is that a good chunk of IE is embedded in the OS so randomly replacing bits of the OS with older versions gets a bit hairy. However is it really too hard for them to test a few configurations of DLLs to get it to work? It's a shame that Firefox can host a foreign IE renderer, but IE can't.
On the other hand Microsoft wants to sell you VirtualPC.
So you install an extra 1Gb of RAM, ignore Microsoft's advice about buying VirtualPC and get VMWare for free instead and set about an edit/compile/switch to vmware/test cycle. You might need to buy a copy of MSDN too because I seem to remember that it is illegal to install the same copy of XP twice on the same machine, but I could be wrong there.
Or
DWR has been using HostedQA recently. HostedQA for me is JUnit + Cruise Control + Selenium + an army of browsers. We've been testing DWR using HostedQA for a while now and it rocks. It's helped us find bugs, and the plan is to set it up so we can test with a whole bunch of browsers so I don't even have to mess about with Firefox profiles. To a certain extent it can make the edit/compile/test cycle an edit/check-in cycle.