In alphabetical order:
China Glaze Emerald Fitzgerald: I remember when I first saw swatches of Emerald Fitzgerald, I loved how it looked and loved its' adorable name! I tried to resist, but gave in when I went to Sallys specifically to pick up only Ingrid. I wore this first (before Ingrid!) and fell in love! OPI Cuckoo for this Color is a dupe.
China Glaze Ingrid: I was lemming this polish as soon as Vintage Vixen swatches came out! It was the only polish I knew I would love and wear (since it is office appropriate) and it did not disappoint! The gold shimmer is subtle, but in good lighting, POW!
Essie Going Incognito: I too tried to resist buying this polish (I hardly ever wear OPI JiTNB), but when faced with a 3/$20 "sale" on Essie, I took it home anyway :) After putting it on, I fell in love! DBF also loves this shade and is sporting it as a secret pedi... shhh don't tell him I told you!
Essie Lapis of Luxury: When I ordered the Resort collection minis-cube, I had my eye on Turquoise and Caicos. But Lapis of Luxury became the star for me! Just look how squishy and dreamy this is... ahhh... I bought a full size recently :) I think Orly Snowcone is a similar shade.
Essie Limited Addiction: I tried this after I had submitted my Top 20 list, but it quickly become a new favourite! I adore this shade!
Essie Sew Psyched: I couldn't decide whether to list RBL Diddy Mow or Essie Sew Psyched on my Top 20 list, since they are identical in color, finish, application, and I actually like both brushes. So I chose the one with the preferred name (as suggested by NB) so here you have it! I took some comparison pictures between the two, and then promptly forgot what was on what nail, so I deleted the pics. I should redo the comparison some day for you skeptics!
Essie St. Lucia Lilac: I purchased this from a blog sale a while ago, and realized it is the perfect pale purple for my skintone! Instant Top 20 for me! OPI Rumple's Wiggin' is similar, but cooler. I like how the Essie is warmer toned :)
Illamasqua Muse: This was my first polish over $12 and let me tell you, it is worth every penny!! Formula is perfect and I love the color! This totally kicked SH Fairy Teal off the "best teal creme" throne at first swatch! My only complaint is that the fake/removeable cap does not sit straight on the actual cap.
Milani Dress Maker: I still remember finding the display at CVS and squealing in delight. I was with some out of town friends who were entertained by my reaction. I tried it on and LOVED it, even though it required a bit of work to apply. Later on, confirmation that it was an exact Chanel Jade dupe caused me to panic and buy many, many backups. I sent one to my Canadian friend as well, since they do not have access to Milani! I hope she enjoys it as much as I do. Similar polishes are, of course, Chanel Jade, and also its other dupes Catrice Sold Out Forever, Claire's Dream Catcher, and a Charlotte Russe I can't remember the name of!
Nina Ultra Pro Never Glum Plum: I bought this online on a whim during one of Sallys recent online sales. There is something just delicious about this creamy shade, and I prefer it to Revlon Perplex (this is relevant because both are considered "similar" to Chanel Paradoxal). I believe Essie Smokin Hot is similar to Never Glum Plum.
OPI Absolutely Alice: I had many opportunities to buy this when it first came out, but always passed it up. I never though I would wear, or like, a true glitter polish like this. Then in September, while on vacation in the UK, I noticed a Sallys going out of business. They were selling off all their OPI for 3GBP, and had more than 6 AA
OPI Funky Dunkey: One of my first OPI polishes gifted to me by an old friend back home in Canada (I just sent her a Christmas package with lots of lemmings!), it was love. I forgot how much I loved it during the last few months of rabid collecting, but every time I go to put it on, I am surprised by how much I love it! There are many near-dupes for this polish: RBL Mismas (regarded as the "original" of this shade, I believe?) and ChG Grape Pop.
OPI Smitten with Mittens: I passed this up the first time I saw it at my local pharmacy. When I came home and looked up swatches, I went back the next time I had a $10 off $20 coupon. This is a really pretty shade, but I wish more gold would show on the nail. A similar polish to SwM is SH Fireberry Red. While it is definitely a darker colour, in the shade, they are remarkably similar.
Orly Country Club Khaki: One of the first polishes I knew would make my Top 20 at first swatch and has stayed there since I got it. This is what I wanted OPI TMF to look like (that pulled insanely mauve on me!) and use this as my go-to "underwear".
Orly Galaxy Girl: Grabbed this on a whim when I went to Sallys specifically to acquire Space Cadet. Yet this polish made my Top 20 while Space Cadet did not. Galaxy Girl is beautiful on its own and layered on other polishes. I love to wear this over a dark, taupe creme. It's safe for my workplace, but has sparkle and duochrome to keep me interested :)
RBL 360: I love the dusty quality and secret shimmer of this polish. So pretty! Picked it up during the last RBL 50% off sale. As much as I love this polish, I don't think I would have paid full price :)
$OPI Ocean Love Potion: I love this colour more than I think I should! Misa Dirty Sexy Money is a dupe, but this was easier for me to find (ordered during Sephora's F&F this fall).
Sally Hansen CSM Fedora: I had been lemming this polish for a while, before I sent DBF on a mission to acquire this (and SH Sequin Scandal) at Ulta. This polish is now my favourite neutral and a go-to polish when I need a colour-cleanse. I'm not in love with these huge paddle brushes because of my small nailbeds, but this polish is too beautiful to punish! $OPI Under My Trench Coat is a dupe.
Sally Hansen XW Concrete: Such an unassuming colour in the bottle, but so flattering on the nail! Many of these colours pull quite purple on me, but I don't mind it with this one!
Zoya Veruschka: This recent addition to my collection quickly moved into my Top 20 list upon first swatch. One of my few "suede"-style matte polishes, this one is gorgeous both matte and shiny. So much depth and sparkle! OPI HTAT Suede is a similar polish.
(with topcoat) 
