Not entirely - I'm not familiar with AMD, but the big difference between chipsets within a generation for intel is really the supported hardware and features. With the SB chipsets, the Z P and H designations determined if various combination of onboard video support and caching were supported - the Q series was a P series (no onboard video IIRC) with Vpro. Likewise for the IB family, the chipsets with "77" in their names support rapid storage and the 75 series dosen't.
Otherwise, practically there should be little difference, with identical storage and PCI chipsets.
Unfortunately, there can be performance differences between the SAME chipset (due to other hardware choices), so be sure to consult benchmarks when making your decision. These may include additional pci controllers, additional disk controllers and so on.
In this case, the H series (so you can use both onboard and additional video cards) would very likely be the best option - they're the cheapest. Also consider the newer Ivy Bridge boards since they have newer/better chipsets, are often backwards compatible with Sandy Bridge chips. If you get an older SB board, research,and get a board with Ivy Bridge compatibility for future upgrade options, since SB boards are forwards compatible.