[trebleshot]

For anyone new to the line, I would recommend any of the following:

Leader ($40-45): Megatron, Ultra Magnus
Voyager ($22-25): Shockwave, Grimlock, Bulkhead
Deluxe ($12-15): Cyb. Mode Optimus Prime, Blurr, Swindle, Lockdown, Soundwave, Swoop, Jazz, Oil Slick, Prowl
Activator ($7-8): Bumblebee, Starscream, Grimlock, Megatron
Legend ($5-6): Starscream, Prowl, Optimus Prime, Bumblebee

Some to stay away from, no matter what:
Activator Lockdown (horrible toy), Supreme Optimus Prime (any other size class version of Optimus is better than this one, not to mention the price).

I would also recommend the Jetfire/Jetstorm 2-pack ($22), but only after you've gotten your feet wet with the above list and decided you liked the line and want more. Also, several of these may no longer be at your local Wal-mart anymore, but you should be able to pick most of them up from HTS or ebay for a reasonable price.