Third, use the advice from the 4e DMG Encounter Building section; it actually has lots of great advice I've seen new DMs ignore, such as not overwhelming yourself with too many monster types in a single encounter.
True; I find no more than 3 different Standard monster types is ideal. Elites may count double; Solos certainly count treble - my best experiences with Solos are when they really do fight the PCs solo, letting me really focus on using all their powers, auras etc properly. You can always add a bunch of simple minions to your 3/2/1 group for more threat & flavour.