Personally, my two favourite jobs happen to be DRG and SMN, but I've levelled so many jobs and only actually got one (DRG) past 40 so far.
Anyway, if you want to play as a DRG and SMN too at one point you will be best off levelling both WAR and WHM, not necessarily at the same time.
Personally, the route I would take would be:
MNK to 18. It's a popular job for parties and in the lower levels, lack of subjob doesn't affect it *too* much. It's a great sub for WAR too if you don't have NIN at your disposal.
At 18 switch to WAR once you got your subjob quest finished. A WAR/MNK is a lot more effective than a WAR without a sub. Take WAR to 30 (to unlock the subjobs) or 37 so it'll never be a gimped sub.
Then you're set until level 60-75 with DRG. Your subs are there, ready at your disposal.
Reason I chose the melee jobs first of all is that a WHM without a sub will find it a little more difficult without the extra MP you'd get from subbing BLM.
For your SMN, the route I took from 10 onwards was BLM/WHM to 20, WHM/BLM to 34 (I got bored. I'll get the last few levels soon. And I got delevelled, so it's now 33) and then SMN for however far you want.
You've picked two fantastic jobs to play. DRG does have it's fair share of people who don't like the job, but just remind yourself that you have a dragon and they don't. DRG is a hefty damage dealer and has some traditional and fun abilities.
SMN is now my main job (but far from my highest). I read through countless forums and websites and became more and more passionate about levelling it more and more. So far I'm at level 27 and I'm yet to find a job more versatile than the SMN. It suits me perfect.
But, hey, this is all *my* advice. Feel free to follow that route if you wish. Remember that ultimately it's your decision, but you must live with the consiquences of them. By that, I mean that you could always be a BLM/WAR if you wanted to. Noone could stop you, but you'd receive very few party invites (if any) and quite a bit of stick for it.
Edit: I forgot that someone mentioned about which race to pick, so I'll garble on a bit more about that too.
First thing's first: Any race can do any job - it's the player's ability that makes them good or not.
A Taru would have a natural advantage over the other races in SMN because of their naturally high MP pool, but a Galka with MP+ equipment could do the job just as efficiently.
On the flipside, if you picked a Taru, you'd have to probably concentrate stats into STR for your DRG because Tarus are naturally "weaker" than the other races.
I chose a Mithra because they look good and I wanted to become the best Thief in Vanadiel. Mithra's naturally high DEX and AGI make them great thieves and that ultimately sealed my decision. But generally, they're all rounders.
A small round up of the races, then?
Galka: Massive vitality and health pool. Little magic points.
Elvaan: Massive strength and high mind. Little magic points (but more than Galka). They also have very high health pools.
Humes: All-rounders.
Mithra: All-rounders that have higher DEX and AGI than the other jobs, but also slightly less in... err... I forget, but it balances up with Humes >.<
Tarutaru: Stupidly high amounts of magic points and very high INT, but the smallest health pool, strength and I believe vitality too.
Edit 2 (sigh): I was reading through some of the above posts and saw that if you're going to level DRG, use a polearm for WAR.
I strongly disagree with this and would recommend you use the best weapons for your current job. WAR, I'd recommend Great Axe (and try to keep your Axe capped too), WHM I'd say use a club. When you unlock DRG, you'll be capping your polearm skill at every level anyway from personal experience.
On every job in my signature the "best" weapon for that job is capped with the exception of WHM and SMN due to the fact that I don't melee with them.
I've never been in a "skill-up" party except to level my regular axes for WAR/NIN.
To use a polearm with a WAR will mean that if you wanted to take WAR post-30/37 then you'd have your best weapons (G.Axe and Axe) uncapped and in need of levelling for weapon skills and better damage.
Edited, Wed May 17 22:00:26 2006 by Unohana