Vitoria-Gasteiz is the capital of the Basque Country and the seat of its regional government, but it remains remarkably under the tourist radar compared to Bilbao or San Sebastián. It's a pleasant, walkable city with a well-preserved medieval old town, a ring of parks and green corridors — the Anillo Verde — that earned it the title of European Green Capital in 2012, and a lively pintxos scene that doesn't cater to tourists so much as to the locals who actually live here.
The old city sits on a low hill, with its medieval streets radiating outward from the Cathedral of Santa María — currently the subject of one of the most engaging restoration projects in Europe. The 19th-century expansion below is tidy and bourgeois, full of covered arcades and good bars, focused around the Plaza de la Virgen Blanca and the colonnaded Plaza de España. Spanish and Basque are both spoken; English less so than in Bilbao, which makes the city feel more genuinely Basque.
Time a visit for the Jazz Festival in July or the patron-saint Fiestas de la Virgen Blanca in early August if you can — they are the loudest, best weeks of the year. Otherwise, plan on a couple of days of slow walks, gallery visits at Artium, pintxos along Calle Cuchillería, and a side trip into the Salburua wetlands on the edge of town.