Best for mostPenguin (Davies) · 2006
For most readers the Penguin Classics edition is the right Jane Eyre — a clean, readable text with Stevie Davies's helpful introduction and notes, at a paperback price. Enough apparatus to orient you, not so much it crowds the novel. This is where I'd start.
Best for studentsNorton Critical (4th ed.) · 2016
The Norton Critical Edition is the student's Jane Eyre — the text plus Brontë's letters and juvenilia, criticism, and essays on the film adaptations. Denser than you need for pleasure; ideal for study.
Most annotatedOxford World's Classics · 2000
Oxford World's Classics offers the scholarly middle — a strong introduction and fuller explanatory notes than Penguin (over 400 of them), in a sturdy edition. A good choice if you want more annotation as you read.
Charlotte BrontëJane Eyretr. Free (public domain)
FreeFree (public domain) · 1847
Jane Eyre is public domain and free everywhere. Free and complete — fine for a re-read, though a few notes help with the Victorian references the print editions supply.