iPods, bark, and stuffed animals?

Slaves and spices.

Gold (and silver and gems and jewels). Slaves. Spices. Furs. Sugar (and sugar derivatives, like rum). Exotic luxury goods and novelties (caged songbirds, unusual animals, objects d'art, etc.)

Also: criminals, exiles, relgious troublemakers, and soldiers. Tobacco. Coffee. Tea. Silk. Manufactured goods that couldn't be made in colonies (machine tools, guns).

It all seems to be stuff that:
1) Has a high value-to-weight ratio
2) Can survive rough travel conditions for long periods
3) Lacks adequate subsitutes in their market (no silkworms or tea in England - they HAD to ship it in)

"It depends..."

Actually, it depends a LOT on who and where to. British, French, or Spanish colonies and shippers might find that, because of mercantilist restrictions on colonial trade, some goods that might otherwise be produced locally or shipped only a short distance had to be imported across vast oceans.

But aside from that...
All manner of luxuries: fine furniture, silver, high fashions, timepieces, linens rugs & tapestries, precious metals and jewels.

Processed goods: Tobacco, sugar, rum, textiles, salted fish, salted meat (Australia!), rifles, cannons, gunpowder, glass, books, complex equipment and machine tools, manufactures in general.

Bulk Goods: Spices, fish (where else does it come from!?), slaves, Germans, Irishmen, bibles and armies.

Really bulky goods: wool, cotton, grain - America's control of New Orleans following the Wa of 1812 greatly increased grain exports from the Mississippi and Ohio river systems; American cotton fed British factories, and colonial Australian wool was bound for British markets.

I'd have been very tempted by the lazy answer/question: "What goods were transported across oceans before, say 1830? [Because it was probably worth transporting them.]" The interesting follow-on questions then would be "what goods were worth transporting, but weren't actually transported? Why?"

Drugs. Molasses for rum. I don't think any ores other than precious gold/silver. No petroleum, obviously. Whale oil, though. Whalebone. Porcelain.

All kinds of stuff we now make artificially--rubber (if vulcanization had been discovered by 1830), dyes, um...

Lumber (esp. tropical lumber?)? Live animals (like prize steer)? Canned exotic fruit (or was it not worth the expense?) Any significant volume of chemicals or chemical precursors?

Alcohol.
Depends on your definition of ocean of course, but port and sack were shipped to England by 1590 (we have Falstaff telling us so) and presumably earlier.
Wheat, Egypt to Rome?
Timber? Royal Navy masts were from the Baltic.
Tin? Known that the Phoeniceans brought it from Cornwall.
Spices, obviously.

As noted above, a surprising variety of items we no longer consider to be of great value. However, the role of the supercargo is underappreciated, as they attempted to make a profit on each part of the journey, buying and selling before reaching the final destination. Excellent (if possibly dated) discussion in Braudel's History of the World.

What goods will be worth transporting to other star systems?

It is physically possible to produce silk in England, with some effort and artificial help, just as it was possible to grow pineapples in Jersey or (as Adam Smith noted) wine in Scotland. Indeed, in the Second World War British silk production was important for parachute manufacture.

It was not only the colonies that found they were unable to produce goods locally because of mercantilism and so had to import them. In their ignorance the ungrateful Virginians never realised that British mercantilism actually favoured them, by stopping Gloucestershire tobacco production and Ulster linen (though before the cotton gin only certain kinds of coastal cotton were economic, they were already being grown in the 18th century).