Recently, other than seeing large world type sets, like what I am currently doing and getting myself into real trouble, I start to see quite specific genre of collecting coins.

I have seen people just collecting by years, or by themes, such as ships, scientists, certain type of animals etc.

What is yours?

My collecting emphasis is on Flying Eagle and Indian Head Cents - one of each year and mint - no patterns or proofs. US Large Cents - I'm concentrating on the Late Date Cents with the first aim of putting together a set of one coin per date - regardless of variety. Then on to Mid Date and then Early Date with the same criteria.

I've been re-evaluating my collecting - again
I seem to do this every other month or so.

I'm still going to continue with the British Victorian Type Set, British Type Set 1902 onward (pre-decimal), and British Shillings - milled coins, by type.

I sold my US Type Set a while back because I was dissatisfied with most of the coins I had, and now I have restarted with an eye towards better quality coins than I had before.

I was also dissapointed in my US Half Cents and Large Cents, so I sold them and have started another collection of Large Cents, going after middle dates first (by date), then late dates (by date), then I will select a few years from the middle dates (1818 and 1820 for now) and collect those by variety. When that one is well underway, I'll start another Half Cent collection, by date and major variety.

Hmpf ... I should live so long

My big theme is a world set for my birth year--any circulating coin from 1963. Outside of that, there's the science set I mentioned as a possibility in another thread, but that's not yet begun.

Oh boy.

US modern circulation coinage business and proof.
US Commemoratives.
World Mint/Proof sets from 1974, 1980 and 1992.
Commemoratives from Russia, Poland, Hungary, Czech Republic, Germany, Austria, Sweden, Norway, Denmark, The Netherlands, Finland, Belarus, Latvia, Lithuania, and more.
Coins with Medieval people on them, bridges, religious themes, military themes.
Big silver peices that catch my eye.
Complete set of Silver American Eagles, Austrian Kookaburras and Silver Brittanias.
Complete set of Commemorative coins of Switzerland.
Exonumia that catches my eye.

That's all I can think of right now.

Coins of Gaul from the beginning to medieval. That lets me tap into Greek, Celtic, Roman, Merovingian, Carolingian, Royal, and Medieval France. That is an impossible range to collect one of everything, so I sample across bronze and silver with designs that catch my eye.

Specific themes within that topic:

Religious themes (temples and altars)
Celtic PIXTILOS coins (Carnutes region ca. 40 BC)
Roman emporers from Gallic mints
regional issues from the area of Chartres and Blois
Carolingian by ruler, coins of Paris
Medieval tête chinonais pieces from the region of Chartres/Blois
Aluminum world type coins
Aluminum world tokens and medals of interest with an emphasis on history and artistic qualities
Aluminum trade tokens by US state (representative "Good For" token from each state)

odds and ends that interest me such as prehistoric art on coins and medals.

All numismatic material I can dating from 1789->1815, primarily European. I extend beyond those dates when the subject is someone who was a "player" during the main period. This means George III stuff both before and after as well as others like Louis XVIII or George IV.

Any items I collect not in this theme are almost entirely the result of my "winnings" at our monthly coin club meeting. I buy tickets for the door prizes and therefore end up with a lot of non-collection specific items. My grandson and new daughter end up with most of these.

I have always been a date, mint mark collector. I am putting together a set of IHC Fine or better, Jefferson nickels BU, and also a US type set. I also have many other side projects like Canadian large cents, British pennies. However I try to stick to my type set.

Great Britain - Mainly 1/2d, 6d and 1s.
Hong Kong and Kwangtung type sets - both nearly complete excluding keys.
Turtles - circulating issues only.

Then there's lots of random stuff and 1-offs

That is okay Bunny, when you catch your breath you can come back and add in the other 263 genres you collect

Russia, Scotland, Portugal, Ukraine, English Tokens, for coins. For paper money, Ireland, Portugal, Czech, Italy, Spain.

I collect virtually any coin or unc note that I dont have yet, but I put special attention to:

-bimetallic coins
-commemorative circulating euro coins
-polymer banknotes
-mexican revolution banknotes

Portraits

Coins of the 12th century Anglo-Norman realm and their contemporaries; including those of Anjou, Aquitaine and Blois. I decided to go for a family tree approach, i.e William the Conqueror's decendents. Due to the expense of coins of William Rufus i decided to focus purely on the 12th century since he died in 1100 and thus i can sweep that difficulty under the carpet. Although one of William I's decendents is out of the equation, his other decendents; Robert of Normandy (+ offspring), Henry I (+ offspring) and Adela (+ offspring)were still around during the 1100s.

Only two other collections getting a look in besides this;

the Roman gods and those Anglo-Saxon coins.

So i have three areas. Although at the moment i have no real inclination to buy any more coins for the forseeable future.

Knowledge.