It's great to level up with a few of the engineers - from memory Felicity, Martuk, the one that does hull stuff and Palin (I think) you need to unlock them to give it to them though - Felicity and Martuck are both quite easy to unlock (see the forums) Metalloys for Felicity used to be on sale at Darnelle's progress in Maia (don't know if they still are). Felicity and Martuk give you access to FSD range upgrades so you can potentially add 50% to your range, great for covering distance as an explorer and for moving combat ships around the bubble in an easier fashion. They (esp. Felicity) also have some other things that they do a bit of which can be really useful - like drive tuining for thrusters.
Carrying exploration data isn't quite like carrying cash if you die/get shot down you loose all that you haven't sold.
You can also sell it to gain rep with local factions especially.
You could wait for a comunity goal - every now and again there will be an appeal for exploration data from a minor faction somewhere (or somtimes a major faction). Risk is that these attract griefers so watch out (or go in pg).
I believe getting to a certain rank with Li Yong Ri (sorry for spelling don't have time to check) gives you a benefit of doubling the pay out (or at least getting paid more) for your data - downside all the interdictions with powerplay to get there and not dying, but if you simply wanted to make money this could be the way to go (but a bit risky)
Otherwise if you want to help a faction out in the game - sell to a certain station to help them boost their influence (my favourite faction is the mischief - have a look at
www.fuelrats.com/tfrm
When I returned fromm my first big expedition (CNE) I got an iridium wing escort to Farseer and sold my data to go from level 4 with her to level 5 and then flew to Martuk and went from Levell 3 I think to 5. FSD range is really useful - I'd highly recomend it.
But there are quite a few options
!
Fly safe commander.
