Stickies – Top notch ‘sticky notes’ program, includes all the features common to this class plus recurring reminders, multiple monitor support, skins, user definable styles, network sharing, conduits to synchronize with your Palm or Pocket PC handhelds, and a nice feature allowing the notes to be attached to any window so when you re-open that window the note will popup. This means you can add notes to things like web pages and the next time you visit that page the note will reappear automatically. (XP/Vista)
TinySpell Spell checker - Impressive little utility which checks individual words on a correct-as-you-type basis in any Windows application. Lots of useful features. (XP/Vista)
FreeSpell Spell checker - Spell checker that can be used in any windows program. (XP/Vista)
WordWeb – Terrific dictionary/thesaurus. Simply select a word in any document and click the WordWeb tray icon. Immediately you'll get a popup with the word's meaning and synonyms. (XP/Vista)