Depends on your definition of state school I suppose. If you take a totally non-selective school that still does well by the vast majority of it's pupils, I'd say that's better than a selective school that surprise surprise gets good results.
How about St Laurence in Bradford-on-Avon (BOA one of the Telegraph best country towns too!) This has a great reputation throughout Wiltshire (great for arts and music, right next to Wiltshire Music Centre and lots of links with it) and I don't think the raw figures do it justice.
Or Sheldon School in Chippenham. 71% achieving 5 A*-C GCSEs in 2006, with 59% getting the five including Maths and English. Again, this is a totally non-selective school, either by ability to pay, academic ability or house prices, so not a bad result. Sheldon is in Ofsted's 'best of the best' honours roll and was listed 25th in the list of best comprehensives in the country according to national league tables. Last year's A level results were better than many respected independent schools locally.
Hardenhuish School in Chippenham is also very well regarded. Again, no selection at all.
Primary schools - many village ones in North Wiltshire very well thought of, including Kington Langley. In Chippenham I think you would honestly be pushed to find a 'bad' school. Some have more mixed intakes than others, and this is reflected in league tables, but then I would never make a decision purely on league tables. In the town itself, St Mary's and St Peter's quite sought after. Ivy Lane good but the tables don't always reflect that. Redland again does well with quite a mixed intake.
Again, statistics can be read many ways. For example one of the schools listed above does not score as well as some of the others on pure SATs figures, but last year was in the top 11% of schools nationally for value-added.
Enough rambling, I'll have a think and ask friends in various other parts of North Wiltshire what schools are like there.