What will Sam spend Gems on?

GW2 is a wholly different MMO compared to others I've played in the past (for the record, that's EverQuest, FFXI, WoW, Anarchy Online, Phantasy Star Online, Phantasy Star Universe, and SWTOR). In past MMOs, the developer made their money by selling monthly subscriptions for playing their games (I realize SWTOR is now F2P, but back when I played it was subscription-based). For example, in FFXI, I paid $13/month plus $1 for each extra character. I had five extra characters, so that was ~$18/month (over the 6 years and one month I played, that amounts to a staggering $1.3k I spent on that game- not including money spent on expansions or the initial game!)

In GW2, there is no monthly fee. Instead, the way which Anet makes their money is through the sale of things through the in-game Gem Store.

In the Gem Store, you can find all manner of different things. From skins, to boosts, to account improvements, to minis, and everything in between.

Personally, I think the vast majority of the crap in the Gem Store is... well.. crap. However, I do spend money on things in the Gen Store now and then.

What follows is my totally opinionated list of things I'm willing to spend money on in this game, as well as those items I'd never buy in a million years.

What would I buy?

Black Lion Salvage Kits
Honestly, this is a no-brainer in my humble opinion. I save all my salvagable exotics (ones which I don't want and which I can't sell for decent money) and salvage them exclusively with these. Sometimes these are daily rewards, map completion rewards, or found in chests, but I still buy them.
Black Lion Chest Keys
Truthfully, I'm torn on these. On the one hand, my success with the Black Lion Chests hasn't been great and I, by and large, think they are a total rip-off. That being said, I've been known to buy keys now and then to gamble at opening chests. I've probably bought 30-40 keys in the three years I've played this game.
Various unlimited use gathering tools
Again, I view these as no-brainers. Never having to buy another pick, axe or sickle is a huge boon. Then again, I bought mine back when they were 800 gems ($10) and soulbound. Now that they are 1000 gems and account bound, I'm not as convinced it's as good a deal.
Account Jump Start
This was on sale for nearly 200 gems off, which was an absolute steal considering the bank expansions and bag slot expansions (which I wanted) would have been more if bought seperately. I actually recorded opening all this stuff here.
Bag Slot Expansion
These unlock more inventory space for your character. I've bought like three of them over the years (not including the two I got from the Account Jump Start above).
Bank Tab Expansion
These unlock more storage space in your bank. I bought one of these, not including the two that came with the Account Jump Start above.
Miniature Spooky Trio
So far, this is the only mini set I've been tempted to buy. In fact, I actually bought it twice so I could also have the Chainsaw Skeleton!

What am I tempted to buy?

These are items I haven't gotten yet, but which I'm strongly considering.

Home Portal Stone
Over time, you start unlocking more and more things in your home, and you want to return to your home daily to gather the various nodes you have there. Unfortunately, getting home can be an annoying disruption since it means you have to go to your racial city, go to the home instance, gather your stuff, then trek back to wherever you were before. This gizmo lets you go instantly to your home from anywhere in the game, and then return to where you left when done. It seems pretty damned handy. But that 900 gem price doesn't excite me, so I've been holding off, hoping to see it go on sale.
Total Makeover Kit
This lets you redo your character's face, skin color, hair, eyecolor, etc. Plus, it includes extra looks not included in the base character creation. It's where I got Meso's awesome hair, Molina's hair and face, and Genova's branchy-do. That being said, I've never spent money on this item. All of kits I've used thus far have been from random drops (probably black lion chests). If I didn't already have plenty, I'd really consider buying them.
Bobblehead Laboratory
This is just silly, stupid fun. Every time someone brings one of these out it's a totaly riot. I've been tempted to buy one, but haven't yet.

What will I absolutely not buy?

Boosters!
There are some pretty cool boosters in the game. That being said, every single booster I've gotten has been for free from daily chests, birthday presents, or other, misc. drops. Thus, I have zero interest in ever spending money on these.
Most miniatures
Spooky trio aside, I think most minis are stupid and overated. I'm not buying any on the TP, I'm selling most of the ones I get as drops, and I'm certainly not going to buy them on the gem store.
Dye packs!
Unless they are included in something else I'm buying, I probably will never buy them by themselves. It's too much of a crap shoot and it's most likely you'll get an ordinary, cheap-ass dye instead of the cool ones you really want. So yeah... dye packs totally ain't worth it.
Outfits and clothing skins
Some of them are pretty cool, don't get me wrong. That being said, none of them seem worth the expense.
Merchant/Banker/TP Express
These are also pretty useful. But, again, I've gotten a ton for free from daily, map completion, and other misc. sources, so I've had zero interest in buying them.
Airship Pass
I have a stack of these from when the airship was a thing (after Lions Arch was destroyed) and I've never used them... With fast travel, instant WvW access, and other vendors, there's little need for these.
Transmutation Charge
I get one every day for PvP rewards, and I've gotten tons from map completion and other free sources. Plus, I had enough of the previous change currency which transfered over to these such that I'll probably never need to buy them.