In reply to El-Mariachi:
For hillwalking/mountaineering boots, I'd consider nothing less. Once I got my first goretex boots I never looked back. Boots are hot in summer whether or not they are lined. Unlike many people, I've never had much problem with the lining being knackered too quickly. Normally, soon after the lining goes the boots fall apart in some way too (especially fabric boots).
For trainers and approach shoes, goretex is great in winter and wet months but less so in summer.