The current go-to scholarly edition is West’s, for both texts. But most editions published in the last 100 years should do (just avoid the French Budé edition for the Odyssey). The more important question is what other materials you’ll be studying alongside the Greek text. Do you read German?
Earlier threads on the subject:
http://discourse.textkit.com/t/editions-of-the-odyssey/12577/1
http://discourse.textkit.com/t/materials-for-reading-homer-in-greek/11836/1
http://discourse.textkit.com/t/recommended-editions-of-the-iliad-and-odyssey/13407/1