dont unlock anything on the recon kit first, I made that mistake and payed for it for days, everyone will tell you to either unlock the support or assault kit first as they both have pretty good std guns and its quicker to badges ribbons with either of these two because of the following
Assault - defrib and med hub, drop it near ppl and hang back from the battle to revive them when needed, comes in real handy defending / attacking the titan
Support - Ammo hub, sentry gun handy again for the titan also getting points round the map by just giving everyone a ammo topup
have a look here for more info anyway and make your mind up
http://www.totalbf2142.com/page.php?do=unlocks
also here to see where to attack vehicles
http://www.totalbf2142.com/forums/showthread.php?t=3640
See you on the battlefield